Motor driven zoom camera

ABSTRACT

The present invention relates to an optical camera having a zoom function in which a focal length can be varied or the variation is actuated by a focal length changing member, and in particular to a camera in which a focal length is varied through a motor. 
     The optical camera has a zoom lens operable by a rotatable zoom ring for changing the focal length thereof. An automatic focusing operation is effected by a control means when the focal length is changed so that an image of an object viewed through a viewfinder remains in focus. The zoom lens can include a motor and an in-exposure zoom control means can be provided for controlling zooming movement of the lens during an exposure operation.

This application is a continuation of Ser. No. 08/108,911 filed Aug. 19,1993, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a camera having a zoom function inwhich a focal length can be varied or the variation is actuated by afocal length changing member, and in particular to a camera in which afocal length is varied through a motor.

The present invention also relates to a motor driven zoom lens camerahaving an image magnification selection mode, and also to a camerahaving a zoom clip mode in which a zoom lens is moved to a predeterminedfocal length.

2. Description of Related Art

A known zoom lens camera has a zoom ring as a focal length changingmember, which can be rotated to vary the focal length. Also known is acamera having an automatic focusing function (AF function) in which animage of an object to be taken is automatically focused. In such a knownAF camera having a zooming function, the AF function is performed when ashutter button is depressed halfway and a photometering switch is madeON.

Consequently, in the known camera, if a photographer attempts to changethe framing by rotating the zoom ring to vary the focal length and atthe same time observes an object through a view finder, unless theshutter button is halfway, no AF function takes place so that a dimmedobject image is seen in the view finder.

After effecting automatic focusing by pressing the shutter buttonhalfway, the photographer fully presses the shutter button to actuate arelease switch to thereby take a picture. A small or narrow focusingrange is set so that a precise focusing can be realized. However, with aparticularly small focusing range, if the focusing is carried out duringzooming, it can take a long time before a precise focusing operation iscompleted or alternatively fine focusing adjustments are repeatedlyeffected so long as no object image is in focus. This can be disquietingto a photographer.

A recently developed and marketed zoom lens camera has a motor drivenzoom lens in which the focal length is varied by a zoom motor. With sucha camera, an image magnification (image size) of an object to be takencan be easily maintained constant whereas in conventional cameras havingno motor-driven zoom function, image magnification has required a highlevel of photographing technique. To this end, it is necessary to set adesired image magnification in the camera body.

The image magnification referred to is determined based on the objectdistance and the current focal length. The object distance is determinedin accordance with the position of the zoom lens which is moved duringthe focusing operation. Consequently, the image magnification can be setonly after the focusing operation is completed.

As already noted, the focusing operation is carried out when a shutterbutton is depressed halfway to actuate a photometering switch.Therefore, upon setting an image magnification, it is necessary for aphotographer to use one hand to actuate a zoom ring to obtain a desiredfocal length whilst using the other hand to press the shutter buttondown halfway. This results in a troublesome operation.

In the above described camera having a motor driven zoom lens, it iseasy to effect a so-called zoom operation in which the zoom motor isautomatically moved to a predetermined focal length, for example, bypressing a zoom set button. However, as is known from the conventionalAF zoom lens camera, the focusing operation takes place when a shutterbutton is pressed down halfway to actuate a photometering switch.

Therefore, if a photographer attempts to effect zoom clipping operationwhile observing an object image through a view finder, the shutterbutton needs to be pressed to obtain the AF function. Otherwise, thezoom clipped object image in the view finder is dimmed.

In the above described motor-driven zoom lens camera, it is also easy toeffect zooming during exposure (referred to as an in-exposure zooming)so that the focal length is varied in the course of the exposureoperation, whereas in conventional cameras having no motor driven zoomfunction, this has required a high level of photographing technique.

However, the direction of the in-exposure zooming in the known motordriven zoom lens camera is predetermined. Thus, if the zooming directionis predetermined to be for a telephoto direction, in the event that thedetected current focal length is at a telephoto extremity, no zoomingcan be practically effected. Consequently, even if an in-exposurezooming mode has been set, no in-exposure zooming is practically carriedout. Thus, there has been a long felt need for solving this problem.

In the known motor driven zoom lens camera for in-exposure zooming, thezooming speed, and the zooming direction, etc., are predetermined on thecamera body side so that the in-exposure zooming takes place inaccordance with predetermined conditions in the course of an automaticpower zooming operation. Thus, a photographer can easily effectin-exposure zooming in accordance with the conditions preset in thecamera body. However, if the photographer tries to effect in-exposurezooming in accordance with conditions different from those preset in thecamera body, for example with a desired zooming speed or zoomingdirection, etc., the preset data must be changed in advance, which istroublesome. There has been a long felt need for an improvement.

As already noted, in the known motor driven zoom lens camera forin-exposure zooming, the zooming speed is predetermined in the camerabody. Accordingly, for example, if the zooming speed is set high inspite of a low shutter speed, there can be two image cores from thein-exposure zooming, i.e., an image core before the completion of thezooming and an image core after the completion of the zooming. Thus, adefective picture results.

With the in-exposure zooming in known motor driven zoom lens cameras,once the shutter speed is set to the bulb mode (i.e., in an openposition), a photographer cannot tell the exposure time, andaccordingly, it is impossible to automatically carry out the powerzooming, for example, for a time equal to half the exposure time.Namely, once the shutter speed is set to the bulb setting no in-exposurezooming can be carried out with the conventional camera.

SUMMARY OF THE INVENTION

An object of the present invention is to eliminate the drawbacksmentioned above.

A particular object of the present invention is to provide an easilyoperable zoom lens camera in which focusing is automatically carried outwhen the focal length is varied without the necessary activation of aspecial switch or sensor, etc.

Another particular object of the present invention is to provide acamera having a motor driven zoom function in which the imagemagnification can be easily set.

Another particular object of the present invention is to provide acamera having a motor driven zoom function in which an in-focus objectimage can always be obtained even when a zoom clipping operation iseffected.

Another particular object of the present invention is to provide a motordriven zoom lens camera in which an in-exposure zooming operation can becarried out regardless of the current focal length.

Another particular object of the present invention is to provide a motordriven zoom lens camera in which the in-exposure zooming operation canbe easily carried out by a manual power zooming operation.

Another particular object of the present invention is to provide a motordriven zoom lens camera in which a clear picture having a single imagecore can be formed in the in-exposure zooming operation.

Another particular object of the present invention is to provide a motordriven zoom lens camera in which the in-exposure zooming operation canbe effected even when the shutter speed is set to the bulb setting.

According to one aspect of the present invention there is provided anoptical camera comprising:

a zoom lens operable by a focal length changing means for changing afocal length thereof;

an automatic focusing means actuable for effecting a focusing operationof said lens in relation to an object to be taken by the camera;

a viewfinder for viewing an image of said object through said lens;

control means for actuating said focusing operation when said focallength is changed.

In one embodiment, said control means actuates said focusing operationon commencement of changing said focal length.

In another embodiment, said control means actuates said focusingoperation during changing said focal length.

In yet another embodiment, said control means actuates said focusingoperation when the changing of the focal length of the zoom lens isstopped.

In this case, the camera further comprises:

means for obtaining distance data of said object from the camera;

means for detecting a neutral position of said focal length changingmeans, wherein said control means actuates the focusing operation whensaid neutral position is detected; and

an image magnification calculation means for calculating a magnificationof an object image in accordance with the object distance data andcurrent focal length when the focusing operation is completed.

The camera may further comprise:

means for storing the calculation results of the image magnificationcalculation means.

In another embodiment of the invention, the camera includes a manuallyoperable shutter button, wherein said focusing operation is actuated inresponse to an actuation of said shutter button.

Preferably, said control means actuates the focusing operation when saidshutter button is actuated within a focusing range which is differentfrom a focusing range of the focusing operation when said focal lengthis being changed.

Conveniently, said focusing range is smaller when said shutter button isactuated than the focusing range when said focal length is beingchanged.

It is preferred that the zoom lens comprises a motor driven zoom lens;and that a motor for driving the lens is located in a body portion ofthe lens.

The focal length changing means may be mounted to an outer peripheralsurface of the lens so as to rotate about an optical axis to vary thefocal length.

In this case, said focal length changing means comprises a zoom ring andis elastically biased to a neutral position so that when the zoom ringis rotated from the neutral position in a clockwise or counterclockwisedirection the focal length is changed.

According to another aspect of the present invention, there is providedan optical camera comprising:

a motor driven zoom lens operable by a focal length changing means forchanging the focal length thereof;

an automatic focusing means actuable for effecting a focusing operationof said lens in relation to an object to be taken by the camera;

a viewfinder for viewing an image of said object through said lens;

an actuating member;

control means for actuating the automatic focusing means operation whensaid actuating member has been actuated;

means for obtaining distance data of said object from the camera; and

an image magnification calculation means for calculating a magnificationof said image in accordance with the object distance data and currentfocal length when the focusing operation is completed.

Conveniently, the camera further comprises means for storing thecalculation results of the image magnification means.

The actuating member may be provided on the zoom lens to be pressed downinto the zoom lens.

According to another aspect of the present invention there is providedan optical camera comprising:

a motor driven zoom lens operable by a focal length changing means forchanging the focal length thereof;

an automatic focusing means actuable for effecting a focusing operationof said lens in relation to an object to be taken by the camera;

a viewfinder for viewing an image of said object through said lens;

an actuating member; and

control means for actuating said focusing operation when said member hasbeen actuated; and

wherein actuation of said member moves the zoom lens to a determinedposition.

Preferably, said focusing operation is commenced when the determinedposition is attained.

The camera can further comprise means for storing a focal lengthcorresponding to said determined position.

The store means electronically store the determined position ormechanically store the determined position.

Conveniently, said determined position corresponds to a position on adisplay of the camera.

The actuating member may be provided on the zoom lens to be pressed downinto the zoom lens.

It is preferred that said control means actuates the storing means tostore a current focal length when the actuating member is pressed downin a set mode, and said control means moves the zoom lens to the storedfocal length and commences the focusing operation when the actuatingmember is pressed down in an operation mode.

The control means can be mounted in the zoom lens; and

the zoom lens can be detachably mounted to a body of the camera.

According to another aspect of the present invention there is provided amethod of conducting a focusing operation in a camera, comprising thesteps of:

a) conducting a searching operation to obtain an effective defocusvalue;

b) checking a focus state of the image; and

c) expanding a focusing range and causing step a) to be skipped during afocusing operation when a predetermined member, other than a shutterbutton, is actuated.

According to another aspect of the present invention there is provided amethod of providing an image magnification mode in a camera, comprisingthe steps of:

focusing a lens to produce an image of an object to be taken; and

calculating a magnification of the image in accordance with a detectedobject distance and current focal length of the lens when focusing iscompleted.

According to another aspect of the present invention there is provided acamera comprising:

a motor driven zoom lens operable by a focal length changing means toeffect power zooming;

means for detecting a current zoom lens focal length,

means for defining a zoom direction, the motor driven zoom lens on thebasis of the currently detected zoom lens focal length; and

in-exposure zoom control means for controlling zooming movement of thelens during an exposure operation in accordance with said defined zoomdirection.

Preferably, the camera further comprises means for detecting awide-angle extremity focal length and a telephoto extremity focal lengthof the lens.

In one case, said defined zoom direction is toward the wide-angleextremity when the detected current focal length corresponds to thetelephoto extremity focal length and toward the telephoto extremity whenthe detected current focal length corresponds to the wide-angleextremity focal length.

In another case, said zoom direction defining means defines said zoomdirection on the basis of differences between said current detectedfocal length and, respectively, the wide-angle extremity focal lengthand the telephoto extremity focal length.

Conveniently, said zoom direction defining means defines said zoomdirection toward the telephoto or wide-angle extremity according towhich gives a larger difference between said current focal length andthe focal length at the wide-angle extremity or the telephoto extremity.

The defined zoom direction may be toward the telephoto extremity whenthe current focal length is between the wide-angle extremity and thetelephoto extremity.

According to another aspect of the present invention there is provided acamera comprising:

a motor driven zoom lens operable by a focal length changing means toeffect power zooming;

means for detecting a current zoom lens focal length;

means for detecting a current shutter speed;

means for detecting a zooming direction of an in-exposure zoomoperation; and

an in-exposure zoom control means for driving the lens to effect zoomingduring an exposure operation at a zooming speed determined on the basisof the current focal length, shutter speed and zooming direction.

It is preferred that said in-exposure zoom control means determines thezooming speed so that zooming is not completed prior to the expirationof an exposure time of the exposure operation.

In this case, the lens can be motor driven at different zooming speedvalues so that an optimum determined zooming speed can be selected fromamong the different zooming speeds.

According to another aspect of the present invention there is provided acamera comprising:

a motor driven zoom lens operable by a focal length changing means toeffect power zooming;

an in-exposure zoom control means for driving the lens to effect zoomingduring an exposure operation;

wherein during a shutter release, automatic power zooming is carried outone of the focal length changing means is not operated or a manual powerzooming is carried out when the focal length changing means is operated.

According to another aspect of the present invention there is provided acamera comprising:

a motor driven zoom lens operable by a focal length changing means toeffect power zooming;

an in-exposure zoom control means for driving the lens to effect zoomingduring an exposure operation, wherein said in-exposure zoom controlmeans carries out a manual power zooming for a predetermined time in aformer half or latter half of an exposure time when the focal lengthchanging means is actuated upon effecting in-exposure zooming.

Preferably, said predetermined time corresponds to one-half of the setexposure time.

According to another aspect of the present invention there is provided acamera comprising:

a motor driven zoom lens operable by a focal length changing means toeffect power zooming;

an in-exposure zoom control means for driving the lens to effect zoomingduring an exposure operation; and,

a bulb setting means for setting a shutter speed in a bulb state;

wherein said in-exposure zoom control means permits manual power zoomingby the focal length changing means during an exposure operation in thebulb state.

It is preferred that said focal length changing means is mounted to anouter peripheral surface of the lens so as to rotate about an opticalaxis so that the zooming direction for manual power zooming isdetermined in accordance with the direction of rotation of the focallength changing means from a neutral position.

In this case, the zooming speed for manual power zooming is determinedin accordance with the angular displacement of the focal length changingmeans from a neutral position.

The zoom lens may be detachably mounted to a body of the camera; and

a motor for driving the zoom lens may be located in a body portion ofthe lens.

The present disclosure relates to subject matter contained Japanesepatent application Nos. HEI 4-306169, HEI 4-306170, HEI 4-306171, HEI4-306172, HEI 4-306173, HEI 4-306174, HEI 4-306175, HEI 4-306176, HEI4-306177 and HEI 4-306178 (all filed on Oct. 19, 1992) which areexpressly incorporated herein by reference in its entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the present invention will now be described with referenceto the accompanying drawings, in which:

FIG. 1 is a block diagram showing an outline of one embodiment of a bodyof a single lens reflex camera to which the invention is applied;

FIG. 2 is a block diagram showing an outline of one embodiment of apowered zoom lens for a single lens reflex camera to which the inventionis applied;

FIGS. 3, 3A, 3B, 3C are block diagrams illustrating one embodiment of acircuit construction for the powered zoom lens;

FIG. 4 is a developed plan view of a zoom code plate of the powered zoomlens;

FIG. 5 is a developed plan view of a focal length code plate of thepowered zoom lens;

FIGS. 6 and 7 are a main flow chart of a lens CPU.

FIG. 8 is a flow chart regarding communication interruption routine ofthe lens CPU;

FIG. 9 is a flow chart regarding 2 ms timer interruption routine;

FIG. 10 is a flow chart of a powered zoom/manual zoom operation;

FIG. 11 is a flow chart regarding PWM 2 ms timer interruption routine;

FIG. 12 is a flow chart regarding PZ pulse count interruption routine;

FIG. 13 is a flow chart of a PWM interruption routine;

FIG. 14 is a PWM control timing chart;

FIGS. 15 and 16 are a flow chart regarding zoom control under constantimage magnification;

FIGS. 17 and 18 are a flow chart of a predictor operation regarding anamount of defocus;

FIG. 19 is a flow chart regarding a standby operation;

FIG. 20 is a flow chart regarding an initializing operation for an AFpulse;

FIG. 21 is a flow chart regarding an initialization operation for apowered zoom position;

FIG. 22 is a flow chart regarding an accommodation operation for thepowered zoom lens;

FIG. 23 is a flow chart regarding a return operation for the poweredzoom lens;

FIG. 24 is a flow chart regarding a stop operation for the powered zoom;

FIG. 25 is a flow chart effective upon receipt of data required forconstant image magnification zooming;

FIG. 26 is a flow chart regarding a constant image magnification zoomingoperation;

FIG. 27 is a flow chart effective upon receipt of input informationregarding constant image magnification zooming;

FIG. 28 is a flow chart effective upon receipt of input regarding acondition of a camera body;

FIG. 29 is a flow chart effective upon receipt of input regarding a bodysequence information;

FIG. 30 is a flow chart effective upon receipt of input regarding an AFpulse from the camera body side;

FIG. 31 is a flow chart effective upon receipt of input regarding a PZpulse from the camera body;

FIG. 32 is a flow chart effective upon receipt of a command whichmemorizes AF pulse data counted in the lens;

FIG. 33 is a flow chart regarding an operation for storing defocusamount, determined by AF on the body side, in a lens memory;

FIG. 34 is a flow chart regarding a storing operation for designated PZpulse data and focal length data;

FIG. 35 is a flow chart regarding an operation for storing defocusamount obtained in the AF on the body side in the lens memory;

FIG. 36 is a flow chart regarding an operation for storing constantimage magnification zooming data received from the camera body;

FIG. 37 is a flow chart regarding powered zooming in a designateddirection or to a designated position;

FIG. 38 is a flow chart regarding the powered zooming operation based onthe data designated by the camera body;

FIGS. 39, 40, 41, 42 and 43 are a lens flow chart regarding an AF pulsecount operation;

FIG. 44 is a flow chart regarding a transmission operation for the powerzooming data on the photographing lens side;

FIG. 45 is a flow chart regarding a standby operation for thephotographing lens;

FIG. 46 is a flow chart regarding a transmission operation for variabledata of the photographing lens;

FIG. 47 is a flow chart regarding a transmission operation for fixedinformation of the photographing lens;

FIG. 48 is a flow chart regarding a transmission operation for an AFpulse count value on the lens side;

FIG. 49 is a flow chart regarding an output operation for focal lengthdata of the photographing lens;

FIG. 50 is a flow chart regarding a transmission operation for constantimage magnification data on the photographing lens side;

FIG. 51 is a flow chart regarding the output of all lens data;

FIGS. 52, 53A, 53B, 54, and 55 are a flow chart of a PZ operation;

FIG. 56 is a flow chart regarding an initialization operation for PZ;

FIGS. 57 and 58 are a flow chart regarding an initialization operationfor AF;

FIG. 59 is a flow chart regarding an operation for checking a supply ofelectricity;

FIGS. 60A, 60B, 61A and 61B are a flow chart of a loop operation for PZ;

FIG. 62 is a flow chart regarding an operation for checking for acompletion of preset powered zooming;

FIGS. 63 and 64 are a flow chart showing a first embodiment of constantimage magnification zooming;

FIGS. 65 and 66 are a flow chart showing a second embodiment of constantimage magnification zooming;

FIGS. 67 and 68 are a flow chart showing a third embodiment of constantimage magnification zooming;

FIG. 69 is flow chart of an operation for AF pulse count;

FIG. 70 is a flow chart regarding an operation for adjusting the AFpulse count value;

FIG. 71 is a flow chart regarding an operation for a PZ terminal point;

FIG. 72 is a flow chart regarding an operation for controllingrotational direction and rotational speed of a zoom motor;

FIGS. 73, 74, and 75 are a flow chart regarding powered zoomingoperation by a zoom switch;

FIG. 76 is a flow chart regarding interruption treatment for the PZpulse count;

FIG. 77 is a flow chart regarding an operation for stopping poweredzooming;

FIG. 78 is a flow chart regarding an operation for braking the zoommotor;

FIGS. 79 and 80 are a flow chart regarding an operation for setting astate of the photographing lens;

FIGS. 81 and 82 are a flow chart regarding powered zooming toward adesignated focal length;

FIGS. 83 and 84 are a flow chart regarding an operation for adjustingdrive speed in accordance with a pulse number, which corresponds to atarget position;

FIG. 85 is a flow chart regarding an operation for correction of PZpulse count when a terminal point is achieved;

FIG. 86 is a flow chart regarding an operation for correcting the PZpulse count when an actual or a present position of the zooming lens isunknown;

FIG. 87 is a flow chart regarding an operation for correcting the PZpulse counter when actual or present position of the zooming lens isunknown;

FIG. 88 is a flow chart regarding an operation of the PZ pulse countwhen actual or present position of the zooming lens is known;

FIG. 89 is a flow chart regarding an operation for correcting the PZpulse count;

FIG. 90 is a flow chart regarding an operation for presetting a focallength;

FIG. 91 is a flow chart regarding drive control for the zoom motor;

FIG. 92A, 92B, and 92C is a flow chart regarding a release operation onthe camera body side;

FIG. 93A, 93B, 93C, 93D, and 93E are flow charts of various operationsassociated with an in-exposure zooming operation;

FIG. 94 is a flow chart regarding an operation for changing modes of apowered zooming;

FIG. 95 is a flow chart regarding an interruption operation for the PZpulse count;

FIG. 96 is a flow chart regarding an operation for controlling PWM ofthe zoom motor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will be explained below with reference to severalembodiments illustrated in the drawings. In the drawings, FIG. 1 is ablock diagram illustrating a main construction of a body portion of anautofocus (AF) single lens reflex camera to which the invention isapplied. FIG. 2 is a block diagram illustrating a main construction of apowered zoom lens to which the invention is applied. FIG. 3 is a blockdiagram of the powered zoom lens circuitry to which the invention isapplied.

The AF single lens reflex camera includes a camera body 11, and aphotographing lens (powered zoom lens) 51 releasably attached to thecamera body 11. Most of the luminous flux of an object to be taken(object flux) incident on the camera body 11 from a zooming opticalsystem 53 of the photographing lens 51 is reflected by a main mirror 13onto a pentaprism 15 constituting a finder optical system, and then aportion of the reflected light beam is directed to a light receivingelement (not shown) of a photometric IC 17. A portion of the objectflux, having been directed to the camera body 11 and made incident uponhalf mirrors 13 and 14, passes through the half mirrors and is reflecteddownwardly by a sub-mirror 19 to be directed onto a macrometric CCDsensor unit 21.

The photometric IC 17 includes a light receiving element for receivingthe object flux. An electric signal generated by the light receivingelement in accordance with the amount of light input into the lightreceiving element is subject to logarithmic compression and A/Dconversion and is then outputted as a digital photometric signal to amain (body) CPU 35. The main CPU 35 performs a predetermined operationon the basis of information, including the photometric signal and filmspeed, so as to calculate an appropriate shutter speed and diaphragmvalue for exposure. An exposure mechanism (shutter mechanism) 25 and adiaphragm mechanism 27 are driven on the basis of the shutter speed anddiaphragm value.

Macrometric CCD sensor unit 21 comprises a macrometric sensor of aconventional phase difference type (not shown). The sensor unit 21includes a split optical system for splitting the object flux in half,and a CCD line sensor for receiving both of the split object flux so asto integrate them (i.e., storing photoelectric transfer and chargesthereof). The macrometric CCD sensor unit 21 outputs the data integratedby the CCD line sensor to the main CPU 35. The macrometric CCD sensorunit 21 is driven by a control circuit for peripheral parts 23. Themacrometric CCD sensor unit 21 includes a monitor element. Theperipheral parts control circuit 23 detects luminance of the object(object luminance) through the monitor element, so as to changeintegration time, based on the detected results.

Peripheral parts control circuit 23 performs a predetermined exposureoperation on the basis of the digital photometric signal and film speedinformation so as to calculate an appropriate shutter speed anddiaphragm value for the exposure operation. The exposure mechanism(shutter mechanism) 25 and diaphragm mechanism 27 are driven on thebasis of the shutter speed and diaphragm value so as to perform theexposure operation. The peripheral parts control circuit 23, uponrelease, drives a mirror motor 31 by means of a motor drive circuit(motor drive IC) 29 so as to perform an up/down operation of the mainmirror 13, and then drives a winding motor 33 so as to wind a film aftercompletion of the exposure operation.

Main CPU 35 communicates with a lens CPU 61 so as to transmit data,command, etc. through a connection with the peripheral parts controlcircuit 23, a group of electric contacts BC mounted on the mount surfaceof the camera body, and a group of electric contacts LC mounted on thesurface of the powered zoom lens 51. Main CPU 35 calculates a defocusamount by performing a predetermined operation (predictor operation) onthe basis of the integrated data outputted from the macrometric CCDsensor unit 21, and calculates rotational direction and rotational speed(i.e., pulse number of an encoder 41) of an AF motor 39. The main CPU 35drives the AF motor 39 by means of an AF motor drive circuit 37 on thebasis of the above rotational direction and pulse number.

Main CPU 35 counts pulses outputted from the encoder 41 in accordancewith rotation of the AF motor 39. When the count value reaches the abovepulse number, the main CPU 35 stops the AF motor 39. The main CPU 35quickly accelerates the AF motor 39 upon initial actuation thereof.Thereafter, the main CPU 35 activates a DC drive mode to decelerate themotor 39 so as to stop the AF motor 39 when it arrives at a targetposition. The main CPU 35 is capable of controlling the AF motor 39 at aconstant speed in accordance with the time between pulses outputted fromthe encoder 41. Rotational movement of the AF motor 39 is transmitted toan AF drive mechanism 55 of the photographing lens 51 through aconnection between an AF joint 47 mounted on the camera body 11 and anAF joint 57 mounted on the photographing lens 51. A group of focusinglenses 53F is driven by the AF drive mechanism 55.

Main CPU 35 has incorporated therein a ROM 35a for storing a programtherein and a RAM 35b for storing predetermined data therein. An E² PROM43 is connected to the main CPU 35 as an external memory means. The E²PROM 43 stores various functions and constants necessary for theoperation or calculation of AF (autofocus) and PZ (power zoom), inaddition to various constants inherent to the camera body 11.

Also connected to the main CPU 35 are photometric switch SWS, which isturned ON upon half-depression of a release button (not shown), and arelease switch SWR, which is turned ON upon full-depression of therelease button, an autofocus switch SWAF, a main switch SWM, which turnsthe electric supply to the main CPU 35 and peripheral equipment ON/OFF,and an up-down switch SWUP/DOWN. The set modes, such as AF mode,exposure mode and photographing mode, and exposure data, such asshutterspeed and diaphragm value, are displayed on a display device 45by means of the main CPU 35. Usually, the display device 45 is providedat two points, i.e., at points on the outer surface of the camera body11 and in the field of view of a finder.

A pair of electric pins BPC are provided for supplying electricity,obtained from a battery 20, to the photographing lens are providedadjacent to the mount of the camera body 11. A pair of electric pinsLPC, which are electrically connected with the electric pins BPC uponmounting, is also provided on the powered zoom lens 51.

Powered zoom lens 51 includes, as a photographing optical system, thezooming optical system 53 which has the group of focusing lenses 53F anda group of zooming lenses 53Z.

The group of focusing lenses 53F is driven by the AF mechanism 55. Thedriving force of the AF motor 39 is transmitted to the AF mechanism 55through the AF joints 57 and 47. AF pulses outputted from an AF pulser59 in accordance with the rotation of the AF mechanism 55 are countedand measured by the lens CPU 61. The lens CPU 61 includes an AF pulsehardware counter for counting the AF pulses.

The group of zooming lenses 53Z is driven by a PZ (power zooming)mechanism 67. A zoom motor 65 for driving the PZ mechanism 67 iscontrolled by the lens CPU 61 via a motor drive IC 63. The amount ofdisplacement of the group of zooming lenses 53Z is counted and measuredby the lens CPU 61, which counts PZ pulses outputted from a PZ pulser 69in accordance with the rotational movement of the zoom motor 65.

Pulsers 59 and 69 include a rotatable disk which has a plurality ofslits extending in the radial direction thereof and spaced in thecircumferential direction in an equidistant manner, for example. Thepulsers 59 and 69 further include LEDs and photodiodes(photo-interrupter), each disposed at opposite sides of each of theslits. The rotatable disk of each of the pulsers 59 and 69 rotatessequentially with the rotation of the AF mechanism 55 and PZ mechanism67. The LED of each of the pulsers 59 and 69 is controlled by the lensCPU 61 to be turned ON/OFF and the output (pulse) of the photodiode isinput in the lens CPU 61.

The absolute position of the group of zooming lenses 53Z (i.e., focallength) and the absolute position of the group of focusing lenses 53F(i.e., object distance to be focused upon) are detected by a zoom codeplate 71 and distance code plate 81, respectively. FIGS. 4 and 5illustrate expanded views of the code plates 71 and 81, respectively.Brushes 73 and 85 slidably engage with an array of codes 71a-71f of thecode plate 71 and an array of codes 81a-81e of the code plate 81,respectively.

Code 71a and code 81a of the code plates 71 and 81, respectively, aregrounded. The plurality of codes 71b-71f and 81b-81e are connected to aninput port of the lens CPU 61. The total range of displacement of thegroup of zooming lenses 53Z is divided by the zoom code plate 71 into 26segments. Each of the segments is distinguished by absolute positional(i.e., focal length) information with 5 bits. The total range ofdisplacement of the group of focusing lenses 53F is divided by thedistance code plate 81 into 8 segments. Each segment is distinguished byabsolute position (i.e., distance of object) information with 3 bits.The relative position in each divided segment is detected by countingpulse number outputted from the pulsers 69 and 59. Indicia 83 of thearray of codes 81e of the distance code plate 81 are provided to detecta central position of each of the segments. A boundary position 72 ofeach segment of the code plate 71 and the indicia 83 of the code plate81 are used as a critical position at which point a count value of eachof the pulsers is corrected.

Powered zoom lens 51 includes, as actuation switches, a switch 75 forchanging zoom speed, and a switch 77 for changing zoom mode. The zoomspeed changing switch 75 includes a switch (the detail of which is notshown) which controls, in the powered zooming mode, tele-directionzooming and wide-direction zooming, and three zoom speed modes in eachof the zooming directions. The zoom mode changing switch 77 includes aswitch for changing between powered zooming and manual driven zooming(D/M), PA switch for changing between a manual powered zooming mode anda plurality of powered zooming modes performed under a constant control,and SL switch for storing actual focal length or the like duringcontrolled, powered zooming mode (i.e., powered zooming mode underconstant image magnification). Although not specifically shown in thedrawings, the zoom speed changing switch 75 will be actuatedsequentially with a zoom operating ring which is inserted into a lensbarrel for rotation and displacement in the optical axis direction, andwhich is normally urged toward a neutral position with respect to therotational direction. The zoom operating ring also includes a mechanismfor mechanically changing between powered zooming and manual zooming.

The contacts of each of the above zoom speed changing switch 75 and zoommode changing switch 77 are connected to the lens CPU 61. The lens CPUperforms a control operation with respect to the powered zoominginresponse to actuation of the switches.

Lens CPU 61 is connected with the main CPU 35 through an interface 62,communication contacts LC and BC, and the peripheral parts controlcircuit 23 of the camera body, so as to perform bi-directionalcommunication with the main CPU 35 of predetermined data. The data to betransmitted from the lens CPU 61 to the main CPU 35 includes, opendiaphragm value AVMIN, maximum diaphragm value AVMAX, minimum andmaximum focal length, actual focal length, actual distance of an object,K-value information, as well as, AF pulse number, PZ pulse number etc."K-value" is intended to be pulse number data of the encoder 41 (AFpulser 59) necessary to displace the image surface, imaged by thezooming optical system 53, by a unit length (for example, 1 mm).

FIG. 3 is a block diagram illustrating the circuit of the powered zoomlens 51 in more detail. The group of electric contacts LC includes 5terminals, i.e., CONT terminal connected to the interface 62, RESterminal, ⁻⁻ SCK terminal, DATA terminal and GND terminal. Through theCONT terminal and GND terminal, a voltage necessary for the actuation ofthe lens CPU 61 is supplied from the camera body 11, and through theremaining terminals, i.e., RES terminal, ⁻⁻ SCK terminal and DATAterminal, communication is performed. In principle, RES terminal isassigned to areset signal, ⁻⁻ SCK terminal to a clock, and DATA terminalto data communication such as predetermined information and commands. Inthis specification, the sign "⁻⁻ " represents a top bar. It is notedthat any elements which are denoted with this prefix correspond to anactive-low or reversed signal. The electricity pin LPC includes a VBATTterminal and PGND terminal. Electric power necessary to drive the zoommotor 65 is supplied from the battery 20 in the camera body 11 throughthe VBATT and PGND terminals. The supply of electricity is controlled bythe CPU 35 by means of the peripheral parts control circuit 23. In thedrawings, reference numeral 91 designates a clock generation circuit.The VBATT terminal is connected both with the motor drive IC 63 and theport P12 of the lens CPU 61, which is for monitoring voltage, through aregister R4.

MAIN OPERATION OF THE LENS CPU

The main operation of the lens CPU 61 will be explained below withreference to FIGS. 6 and 7. Instruction commands are shown in Tables 1and 2. Commands (data) utilized to transmit various camera body datafrom the camera body to the lens are shown in Table 3. Commands utilizedto transmit various lens data from the lens to the camera body are shownin Table 4. A memory map of RAM 61b of the lens CPU 61 is shown inTables 5 to 11.

Flags which are used in the description of the embodiments are shown inTables 12 to 15.

In the main routine, the lens CPU 61 first sets a high-speed actuationmode (Step (hereinafter referred to as "S") 101). The lens CPU 61performs an inhibition of interruption operation, sets stack address,and initializes the port P, and then inputs the present absolute zoomcode from the zoom code plate 71 (S103-S109). Then, the data calculatedbased on the zoom code is stored in the RAM 61b, and a group of data(LC0-LC15 in Table 5) stored in the RAM 61b, by means of communication(former communication) in accordance with a clock signal of the camerabody 11, is transmitted to the camera body (S111). After completion ofcommunication, a 3-ms timer is started (S113).

When the former communication has been completed, KAFEND signal ("L"level") will be outputted from the interface 62 before 3 ms has passedin accordance with the 3 ms timer. However, if the former communicationcompletion signal (KAFEND signal) is not outputted before 3 ms haspassed in accordance with the 3 ms timer, a stop operation (stopping ofclock 91) is performed to break the main routine (S115, S117, S119).When the KAFEND signal is outputted before 3 ms has passed, theoperation has been performed in a normal manner. Accordingly, a commandwill now be received from the camera body 11 by means of communication.If the command received is not a new communication command, identifyingthe camera as one which is suitable for new communication, a stopoperation is performed to prevent mis-communication with a camera bodywhich is unsuitable for the new communication (S121, S123, S119). The"new communication" is defined in this specification as a state in whicha bi-directional communication of commands and data is possible betweenthe camera body and photographing lens in synchronization with the clockof the photographing lens.

When the new communication command is received, a command receiptcompletion signal is outputted to the camera body so as to startpermission of a 2 ms timer interruption, to permit interruption of newcommunication, and to permit other possible interruptions (S123, S125,S127, S128, S129). Accordingly, an interruption operation of the 2 mstimer and interruption of new communication is made possible. The aboveoperations are all initially performed when the main switch of thecamera body 11 is turned on and electricity is supplied from the camerabody 11. While the main switch is on, the following operations will berepeated.

A zoom code is inputted from the zoom code plate 71 (S131). If the zoomcode is different from the previous one, distance code data is inputtedand lens code data LC2, cluding the distance code data, is stored in RAM61b (see FIG. 6. Then, an operation (or calculation) is performed on thebasis of the data of zoom code, so as to store the calculated data inthe lens RAM 61b as LC0-17 and LB4, LBB data (S133, S135, S137). If thezoom code is the same as previous one, distance code data is inputtedfrom the camera body 11 and lens code data (LC2), including the distancecode data, is stored in the lens RAM 61b at a predetermined address(S133, S139, S141).

It is then determined whether there was a stop demand duringcommunication interruption from the camera body (i.e., whether or notflag F₋₋ STANDBY is set), or whether there was an electricity demandduring interruption of the 2 ms timer (i.e., whether or not flag F₋₋LBATREQ is set). When there is no stop demand, or when there iselectricity demand, constant image magnification operation (ISZ) isperformed, followed by NIOST operation (i.e., the process is returned tostep S131 of the main routine so as to repeat the above operation). Theabove corresponds to steps S143, S145 and S147. It is to be noted that"electricity demand" is a demand which asks the camera body 11 (bodyCPU) to supply the powered zoom lens 51 with electricity from thebattery 20 in order to drive the zoom motor 65 via electric source pinsBPC and LPC.

When a stop demand exists and a battery or electricity demand does notexist, a stop operation is performed after making preparation forstopping (i.e., preparation for inhibition of the 2 ms timerinterruption and cancellation of stop). The above corresponds to stepsS143, S145, S149 and S151. The lens CPU 61 stops the clock 91 to enter alow power consumption mode (standby). The stopped state (low powerconsumption mode) can only be cancelled by, for example, communicationinterruption from the camera body, and the process returns to normaloperation (clock 91 operation). When returning to the normal operation,the process returns to step S153 after completion of the communicationinterruption routine. When the stop demand is cancelled or electricitydemand is generated in the communication interruption, the processreturns to S131 after permitting the 2 ms timer interruption andstarting the 2 ms timer. Otherwise, the process returns to step S149 toagain enter the stop condition or the low power mode (S153, S155, S157).

INIT OPERATION

The communication interruption operation, shown in FIG. 8, is performedby the lens CPU 61 and will be explained below. An INTI operation is anoperation to conduct communication interruption in which an operation isperformed on the basis of the commands and data, etc. received duringcommunication. This operation commences when the interruption signaloutput from interface 62 is inputted to the port INT1 of the lens CPU61.

When the process enters the communication interruption, thecommunication interruption is inhibited and command is inputted from thecamera body 11 after clearing stop flag (F₋₋ STNDBY) and NG flag (F₋₋SCKNG, F₋₋ CMDNG) in steps S201, S203 and S205. The process checks theupper 4 bits of the command as inputted and proceeds to an appropriatesubroutine depending on the upper bits (S207 and S229). In each of thesubroutines, an appropriate operation is performed depending on thelower bits. In the illustrated embodiment, subroutines makingidentification from the upper 4 bits include a BL command subroutine,instruction code subroutine, a 16-byte (first half 8-byte data/secondhalf 8-byte) data subroutine, byte by byte data subroutine, and a testmode subroutine (S209, S213, S217, S221, S225 and S229).

If the above 4 bits are not those set out above, the process setscommand NG flag F₋₋ CMDNG and returns to the main routine afterpermitting communication interruption (S227, S231 and S233).

2 ms TIMER INTERRUPTION OPERATION

The operation of the lens CPU 61 when receiving interruption of the 2 mstimer will be explained below with reference to the 2 ms timerinterruption flow chart shown in FIG. 9. The 2 ms timer is a hard timerincorporated in the lens CPU 61 for outputting interruption signals each2 ms. The 2 ms timer interruption is a periodic interval operation whichconducts an interruption operation upon the passing of the 2 ms intervalof the 2 ms timer, provided that interruption is permitted.

In the 2 ms timer interruption operation, all other interruptions areinhibited. Then, a present value is inputted from the AF pulse counterto be stored in lens RAM 61b, and present distance code data is inputtedfrom the distance code plate 81 to be stored in RAM 61b (S303, S305). Ifdesired, the AF pulse number is corrected, and the present distance codeis stored in lens RAM 61b as previous distance code, at a differentaddress, for the next 2 ms timer interruption operation (S307, S309).

The present zoom code is read from the zoom code plate 71 and stored inlens RAM 61b as a present zoom code. The process inputs the state of thezoom mode changing switch 77 and the state of the zoom speed changingswitch 75 (S311, S313). The process proceeds to the DZ operation whenthe powered zoom mode is selected, and to the MZ operation when themanual zoom mode is selected (S315).

DZ OPERATION

The DZ operation and MZ operation shown in FIG. 10 are flowchartsregarding an electrically driven (powered) zoom operation and manual(hand operated) zoom operation, respectively. These operations areperformed by the lens CPU 61.

In powered zoom (DZ) operation, an end point detection operation toidentify if the group of zooming lenses 53Z has reached the end pointthereof is performed (S351).

The flags for controlling the motor, etc. are set depending upon thezoom speed changing switch 75 and control flags, such as flag F₋₋MOVTRG, F₋₋ MOV, etc. PZ pulse, and present value of the focal lengthare inputted to be stored in the RAM 61b. If desired, PZ pulse iscorrected. When the present position of the group of zooming lenses 53Zis unknown, a position initializing operation (PZ-INITPOS) for the groupof zooming lenses 53Z is performed, and the zoom code is stored at adifferent address as a previous zoom code in preparation for the next 2ms timer interruption operation (S353, S355, S357).

If the constant image magnification zoom mode (F₋₋ ISM=1, i.e., ISZoperation) is selected, ISZ memory operation is performed and the stateof zoom switches 75 and 77 are stored in preparation for the next 2 mstimer interruption operation (S357-S361). According to the flag set instep S353, drive control for the zoom motor 65, set-up of interruptionbit-flag, duty ratio up operation for PWM control are performed. If PWMcontrol is conducted, the PWM timer is started (S363). Then, the processpermits interruption and returns to the step concerned (S395).

In the manual zoom (MZ) subroutine, the zoom motor 65 is first stopped,the LED of the PZ pulser 69 is turned off, the battery request(electricity demand) flag F₋₋ LBATREQ is cleared, and the bit of each ofthe PZ lens state PZ₋₋ LST data is cleared (S371, S373, S375, S379).

Data regarding PZ control stored in lens RAM 61b at a given address iscleared, and zoom code is stored in preparation for the next 2 ms timerinterruption operation. PZ pulse number, roughly detected from the zoomcode, is stored in the lens RAM 61b as the present value of PZ pulse(PZPX), and a start value of PZ pulse (PZPSTRT) and PZ pulse counter(PZPCNT) are cleared. The present value of PZ pulse, as roughlydetected, is converted into a present focal length (rough data) to bestored in the memory (S383, S385, S387).

The state of zoom switches 75 and 77 is stored in preparation for thenext 2 ms timer interruption operation. Then, the 2 ms timer is startedto allow 2 ms timer interruption and to inhibit interruption of INT3 (PZpulse count) and INT 2 (PWM) in steps S389 through S393. The processpermits another interruption and returns to the step concerned (S395).

METHOD FOR CONTROLLING PWM

A PWM control method will be explained below on the basis of the flowchart shown in FIGS. 11 to 13. FIG. 11 shows the portion of the 2 mstimer interruption routine, shown in FIGS. 9 and 10, which relates toPWM control. FIG. 12 shows the portion of the PZ pulse countinterruption routine shown in FIGS. 95 and 96, which relates to PWMcontrol. FIG. 13 shows a PWM interruption routine (brake operation)during PWM control. The relationship between the main flow of FIG. 6 andvarious interruption routines will be explained hereinafter. It ispossible to interrupt, by one of the communication interruptions (2 mstimer interruption or PWM interruption), the loops of main flow stepsS127-S131 and S131-S157 shown in FIG. 6. It is also possible to effectthe interruption by one of 2 ms timer interruption, PZ pulse countinterruption or PWM interruption in the communication interruptionroutine. In the PWM control, speed is controlled by increasing ordecreasing a ratio (PWM duty ratio T₋₋ PWMBRK) between a period of timein which power is supplied and a period of time in which power is notsupplied. In other words, a constant speed control is realized byincreasing the PWM duty ratio (T₋₋ PWMBRK) so as to prolong power supplytime to the zoom motor 65 when a PZ pulse is not detected within apredetermined period of time, thereby making the control speed higher,or by decreasing the PWM duty ratio (T₋₋ PWMBRK) so as to shorten thepower supply time to the zoom motor 65 when a PZ pulse is detectedwithin a predetermined period of time, thereby making the control speedslower (see FIG. 14).

Upon starting (i.e., when the motor is brought into actuation from itsstopped state or braked state), the duty ratio is set at the minimum(i.e., the shortest power supply time) and then the zoom motor 65 issupplied with power and pulses outputted from the PZ pulser 69 arecounted. When no pulses are outputted within a predetermined period oftime, the duty ratio is gradually increased. When pulses are outputwithin the predetermined period of time, the duty ratio is decreased.Thus, the zoom motor 65 is driven under acceleration control or constantspeed control so that pulses are outputted at a preset time, period orcycle. Also, by setting the duty ratio at the minimum when the motor isactuated, it enables the photographer to effect a very smooth zoomingoperation.

Whether the zoom motor 65 is driven for the first time is checked instep S401 (i.e., whether or not the flag F₋₋ START is set). The firstdrive of the zoom motor 65 takes place when the zoom motor that has beenstopped or braked is rotated. If the zoom motor 65 is driven for thefirst time, the PWM timer T₋₋ PWM is cleared so as to drive the zoommotor at the minimum speed, and the PWM duty ratio T₋₋ PWMBRK is set atthe minimum value (minimum speed) in step S403. Thereafter, controlproceeds to step S405. If the zoom motor 65 is not driven for the firsttime in step S401, control directly proceeds to step S405.

In step S405, the process sets the pulse duration (pulse period P₋₋PWMPLS) in accordance with the speed set by the zoom speed changingswitch 75, etc. so as to supply electricity to the zoom motor 65 (S405,S407). This means that the zooming speed is controlled so that the PZpulse is outputted at a pulse duration T₋₋ PWMPLS.

The process checks if the PWM drive mode or the DC drive mode is suitedto the zooming speed. If the PWM drive mode is selected, the processproceeds to step S411. If, however, the DC drive mode is selected, theprocess will be returned (S409). In step S411, one increment is added tothe PWM timer T₋₋ PWM. The process checks whether the value, having beenincreased by one increment, exceeds the pulse period T₋₋ PWMPLS. Ifexceeded, PWM duty ratio (T₋₋ PWMBRK) is increased, and if not exceeded,no operation is performed (S413, S415). That is, if the PZ pulse isgiven within a predetermined period of time (T₋₋ PWMPLS), the PWM dutyratio (T₋₋ PWMBRK) is increased to prolong the power supply time, thusprescribing a high speed operation towards the preset speed.

The process will be completed after setting the PWM duty ratio (T₋₋PWMBRK), starting the PWM timer and permitting interruption of the 2 mstimer (S417, S419). It should be noted that steps S407-S419 correspondto times (A), (C) and (D) in FIG. 14, respectively.

When PZ pulse is outputted from PZ pulser 69, the process enters the PZpulse count interruption operation in FIG. 12. In the PZ pulse countinterruption operation, the pulse period (T₋₋ PWMPLS) is compared withthe PWM timer T₋₋ PWM. If the pulse period (T₋₋ PWMPLS) is larger thanPWM timer, a pulse is outputted within the pulse period T₋₋ PWMPLS, andthus the PWM duty ratio T₋₋ PWMBRK is decreased and the PWM timer T₋₋PWM is cleared. If the pulse period T₋₋ PWMPLS is less than the PWMtimer, a pulse is outputted after one pulse period T₋₋ PWMPLS, so thatthe PWM timer T₋₋ PWM is cleared to complete the process at this time(S421, S423, S425).

In the PWM interruption routine in FIG. 13, the process inhibitsinterruption, and brakes the zoom motor 65 so as to inhibit interruptionof INT2 (PWM), while allowing another interruption, and the process isreturned. The operation in the above corresponds to time (B) in FIG. 14.

In the PWM control, the pulse period T₋₋ PWMPLS is set at three stages,i.e., low speed at 8, medium speed at 4, and high speed at 3, dependingupon the speed designated by the zoom speed changing switch 75 etc. ThePWM timer T₋₋ PWM is cleared when the motor is actuated and when theprocess transfers to the PZ pulse count interruption operation uponreceipt of a PZ pulse outputted from the PZ pulser 69. Thereafter, thePWM timer is counted-up in the 2 ms timer interruption routine at S411until after the PZ pulse is outputted. Accordingly, the PWM timer T₋₋PWM indicates a time which is a multiple of the time elapsed since theprevious PZ pulse was outputted. It should be noted, however, that theduration of a PZ pulse is greater than the period of the 2 ms timerinterruption, even in a high speed mode.

For example, when high speed 3 is assigned (i.e., pulse duration T₋₋PWMPLS=3), the time period elapsed since the previous PZ pulse wasoutputted is 2 ms×3=6 ms. When low speed 8 is assigned, T₋₋ PWMPLS willbe 8. The operation during the low speed will be explained withreference to the flow charts illustrated in FIGS. 11 and 12. If, in stepS413 of the 2 ms timer interruption, it is determined that the pulseperiod T₋₋ PWMPLS is smaller than the PWM timer T₋₋ PWM, i.e., more than2 ms×8=16 ms has passed since the previous PZ pulse was outputted, theprocess proceeds to PWM duty ratio increase (S415).

On the other hand, and in the PZ pulse count interruption operation, ifit is determined that the pulse period T₋₋ PWMPLS is larger than PWMtimer T₋₋ PWM during the check in step S421, a PZ pulse is outputtedbefore 2 ms×8=16 ms has passed since the previous PZ pulse was outputand accordingly, the PWM duty ratio is decreased (S423).

As shown above, a constant speed control in which PZ pulse duration iskept constant is made possible, by increasing or decreasing the dutyratio (T₋₋ PWMBRK) of PWM so that the PZ pulse is outputted at apredetermined pulse cycle or period (T₋₋ PWMPLS). The PZ pulse duration,and thus the control speed, may be changed by changing the pulse periodT₋₋ PWMPLS to be set.

CONSTANT IMAGE MAGNIFICATION RATIO ZOOMING

Constant image magnification zooming (ISZ) will now be explained.Constant image magnification zooming is a control in which an imagemagnification ratio m represented by m=f/D may be kept constantregardless of variation in object distance, wherein object distance andfocal length are represented by D and f, respectively.

First, the principle of constant image magnification zooming will beexplained. For clearer illustration, a zoom lens constituted by two lensgroups of a first group and a second Group will be used in theexplanation. Image magnification ratio m of the zoom lens is given byequation 1) below:

    m.sub.1 =x/f.sub.1

    m.sub.2 =f/f.sub.1

    m=m.sub.1 *m.sub.2 =x*f/f.sub.1.sup.2                      1)

wherein:

m: image magnification ratio

m₁ (m1) : magnification ratio of the first group

m₂ (m2) : magnification ratio of the second group

f: composite focal length

f₁ (f1) : focal length of the first lens group

x: amount of advancement of the first lens group from infinite end(amount of displacement)

The amount of advancement upon setting an image magnification ratio x₀(x0), focal length f₀ (f0), and image magnification ratio m₀ (m0) isgiven by:

    m.sub.0 =x.sub.0 *f.sub.0 /f.sub.1.sup.2                   2)

If a focal length f which satisfies the following equation 3) is foundwhen the lens is displaced to x by means of a focusing operation, theimage magnification ratio can be maintained constant:

    m.sub.0 =x*f/f.sub.1.sup.2                                 3)

From equations 2) and 3),

    x0*f0/f.sub.1.sup.2 =x*f/f.sub.1.sup.2

Thus, focal length f, which is to be found, is given as follows:

    f=x.sub.0 *f.sub.0 /x                                      4)

If a defocus amount Δx at the lens advancement amount x is obtained bymeans of AF macrometer, objective focal length f can be calculated by:

    f=x.sub.0 *f.sub.0 /(x+Δx)                           5)

The principle (theory) of constant image magnification ratio zooming isexplained above. In practical (applied) control, however, the amount ofadvancement of the lens is managed by the focal length code plate, AFpulser, etc. The AF pulser is designed so that it will have a linearrelationship with the amount of advancement of the lens.

Thus, the amount of advancement x, x₀ in equation 4) and 5) may bereplaced with an AF pulse number from the infinite end, and a defocusamount with defocus pulse number.

An actual operational method will be explained below. The lens CPU 61performs constant image magnification ratio zooming (control zooming).The operation is performed on the basis of an image magnification ratiosupplied from the camera body 11 or on the basis of object distance andfocal length at a given instance.

(1) When an image magnification ratio m₀ is sent from the body:

(i) provisional set value, pulse number for advancement x₀ and focallength f₀ is obtained from m₀.

First, let

    f.sub.0 =|f.sub.1 |                      6)

let the amount of advancement corresponding to x₀ be X, and usingequation 2):

    m.sub.0 =X*f.sub.0 /f.sub.1.sup.2                          7)

let the AF pulse number per 1 mm of lens advancement amount be k:

    x.sub.0 =X*k                                               8)

from equation 8), 6) and 7), objective advancement pulse number x₀ isgiven as follows:

    x.sub.0 =m.sub.0 *|f.sub.1 |*k           9)

(ii) next, x₀ f₀ will be obtained.

From equations 6) and 9), x₀ *f₀ is obtained as follows:

    x.sub.0 f.sub.0 =x.sub.0 *f.sub.0                          10)

(iii) objective focal length f is obtained.

f is obtained on the basis of the present position (present advancementpulse number) x as follows:

    f=x.sub.0 f.sub.0 /x                                       11)

f is also obtained on the basis of defocus pulse number ₋₋ x as follows:

    f=x.sub.0 f.sub.0 /(x+.sub.-- x)                           12)

(2) When f is to be obtained on the basis of advancement pulse number x₀stored in the lens RAM 61b and focal length f₀.

(i) x₀ f₀ will be obtained from the above x₀ and f₀, using equation 10)as follows:

    x.sub.0 f.sub.0 =x.sub.0 *f.sub.0

(ii) magnification ratio me will be obtained by using equations 7), 8),and 10) as follows:

    m.sub.0 x.sub.0 f.sub.0 /(f.sub.1.sup.2 *f)                13)

(iii) objective focal length f is obtained as follows:

f will be obtained in the same way as (iii) above in 1)

(iiii) f₁ is data peculiar to the lens and is stored in ROM 61a.

ISZ OPERATION

A calculation operation regarding constant image magnification ratiozooming (ISZ) based on the above described principle will be explainedin detail with reference to flow charts shown in FIGS. 15 and 16. Thisoperation is performed by the lens CPU 61.

An image magnification ratio is set by the zoom speed changing switch 75or set-up switch (SL switch). This will be explained later in detailwith reference to FIG. 90.

The ISZ operation is related to the calculation of the preset imagemagnification ratio and to calculation of focal length for maintainingthe preset image magnification ratio. The focal length will becalculated in the case where focusing is required and the case wherefocusing is not required. In each case, calculation is made by thephotographing lens or camera body. When focusing is required, the focallength, image magnification ratio and objective lens advancement amountare calculated on the basis of the amount of advancement of the lensupon focusing. When focusing is not required, image magnification ratioand objective lens advancement amount are calculated on the basis of thedefocus amount and the present focal length.

The process first performs inhibition of communication interruption(SEI) and checks the flags (F₋₋ STIS, F₋₋ ISZM, F₋₋ ISZFOM, F₋₋ ISZXOM)in order to determine the way in which the ISZ operation is beingperformed, on the basis of communication information transferred fromthe camera body 11 (S451, S453, S465, S477, S479). These flags indicatethat communication regarding ISZ has been performed in relation to thecamera body 11. In each communication, the flag is set (stored) in RAM61b. The required operation or calculation will be made on the basis ofthe flags.

F₋₋ STIS designates the flag for carrying out the calculation of ISZbased on the image magnification data transferred from the camera body.F₋₋ ISZM designates the flag for carrying out the calculation of ISZbased on the current value of AF pulse and the current value of thefocal length. F₋₋ ISZFOM and F₋₋ ISZXOM designate the flags for carryingout the calculation of ISZ based on the focal length and AF pulsetransferred from the camera body, respectively. Note that, when both theflags F₋₋ ISZFOM and F₋₋ ISZXOM are set, the calculation of ISZ iseffected. Moreover, F₋₋ ISZFOM designates the flag that indicates thatthe focal length data f from the camera body is to be used, and F₋₋ISZXOM" designates the flag that indicates that the object distance datax from the camera body is to be used.

When constant image magnification ratio zooming is performed on thebasis of the image magnification ratio sent from the camera body 11 (F₋₋STIS=1), communication interruption is permitted (CLI), x₀ ×f₀ isobtained from the above equations 6), 9) and 10) to be stored in RAM 61bat a predetermined address, and interruption is inhibited so as to clearflag F₋₋ STIS (S455-S463).

In the case that the image magnification ratio has been stored andconstant image magnification ratio zooming is performed on the basis ofthe focal length and object distance stored in the memory (F₋₋ STIS=0,F₋₋ ISZM=1), interruption is permitted, x₀ ×f₀ is calculated from theabove object distance (advancement pulse number) x0 and focal length f₀,image magnification ratio m0 is calculated using equation 13) so as tobe stored in RAM 61b at a predetermined address, communicationinterruption is inhibited, and flag F₋₋ ISZM is cleared (S465-S475).

In the case that constant image magnification ratio zooming is performedon the basis of focal length f₀ sent from the camera body 11 and objectdistance (advancement pulse number) x0 (F₋₋ STIS=0, F₋₋ ISZM=0 andISZFOM=1, F₋₋ ISZXOM=1), x0·f0 is first calculated on the basis of focallength f₀ as received and object distance x₀ so as to be stored inmemory. Image magnification ratio m₀ is calculated from equation 13).Interruption is inhibited and flags F₋₋ ISZFOM, F₋₋ ISZXOM are cleared(S477-S489). In a case other than the above, it is noted that nocommunication regarding operation is conducted in relation to the camerabody 11. Accordingly, no operation is performed in such a case.

Thereafter, whether or not the defocus amount Δx sent from the camerabody 11 is effective, is checked in accordance with the state of theflag F₋₋ FPREOK in step S491. If the flag F₋₋ FPREOK is set at "1", theflag F₋₋ FPRE is set in step S493. Conversely, if the flag F₋₋ FPREOK isnot set at "1", flag F₋₋ FPRE is not set. The flag F₋₋ FPREOK indicatesthat the calculation to obtain a target value of focal length inaccordance with the defocus pulses has been carried out. The flag F₋₋FPRE indicates commencement of the calculation (steps S503-S513) toobtain the target value of focal length in accordance with the defocuspulses in the constant image size mode. Although the defocus amount andthe predictor value are used for the calculation, they represent thedefocus pulses.

Whether or not the mode is the ISZ zoom mode is checked in step S495. Ifthe mode is the ISZ zoom mode, whether the latest position of thefocusing lens 53F (i.e., the object distance) is detected is checked,that is, whether or not the flag F₋₋ AFPOS, which indicates that thelens CPU correctly recognizes (or counts) the current position of thefocusing lens 53F, is set at "1" is checked (step S497). If the flag F₋₋AFPOS is set at "1", control proceeds to the FPRE-OP operation in whichcontrol is effected in accordance with the predictor calculationresults. Conversely, if flag F₋₋ AFPOS is not set at "1" in step S497,control proceeds to the ISZE operation.

If the mode is not the controlled zooming mode, flags F₋₋ FPREOK, F₋₋FPRE, F₋₋ ISOK are cleared. Then, the content at a predetermined address(LNS₋₋ INF1) and the logical sum of each of the bits [00000111B] arestored at a predetermined address (LNS₋₋ INF1). Thereafter, the processpasses through the ISZE operation (S495, S498, S499).

FPRE-OP OPERATION

The (FPRE-OP) operation, shown in steps S501-S513 in which objectivefocal length f is obtained on the basis of a predictor amount, will beexplained with reference to the flow chart shown in FIG. 17. Thisprocess is performed by the lens CPU 61 when predictor amount is sentfrom the camera body 11 during communication of the CPU with the camerabody 11 (during this communication, flag F₋₋ FPRE is stored (memorized)in RAM 61b), or when steps S453 S463, S465-S475 or S477-S489 areperformed to change or modify x₀ f₀ values by the communication of theCPU with the camera body 11 regarding ISZ and flag F₋₋ FPRE is set inS491-S493. The flag F₋₋ FPRE is a flag which determines whether or notthe calculation (f=x0 f0/(x+Δx)) is performed to obtain objective focallength f based on predictor amount.

When entering this operation, the process checks if the flag F₋₋ FPRE isset so as to determine whether the operation based on predictor amountis to be performed (S501). If flag F₋₋ FPRE is not set, the processjumps to S515. Otherwise, the process proceeds with the followingoperation.

First flag F₋₋ FPRE is cleared and communication interruption isinhibited. Objective focal length f is calculated from equation 12),utilizing predictor amount, and communication interruption is inhibited(S503-S509). Then, the objective focal length f is transformed toobjective PZ pulse number from a WIDE end so as to be stored in RAM 61bat a predetermined address (PZPFPRE). Flag F₋₋ FPREOK which indicatesthat the operation based on the predictor amount is effective is set.Then, the process proceeds to step S515 (S511, S513).

S515-S521 are steps in which the objective focal length f is calculatedon the basis of present AF pulse (advancement pulse number).

In S515, permission of interruption (CLI) is performed. Then, theobjective focal length f is calculated using equation 11) so as to bestored in RAM 61b at a predetermined address (ISZ₋₋ FL,H) and theninhibition of interruption (SEI) is performed (S515, S517). Theobjective focal length f calculated above is transformed into objectivePZ pulse number from the WIDE end. The transformed pulse value is storedin RAM 61b at a predetermined address (PZPF) in S519, S521.

The content of bits 3 through 7 of LENS₋₋ INF1, calculated in S529, willbe explained below. LENS₋₋ INF1 is information which is periodicallysent from the lens to the camera body by means of communication. Bits 3through 7 are information regarding ISZ mode.

Bits 6 and 7 are flags which indicate whether the objective PZ pulse(PZPFPRE or PZPF) obtained by the ISZ operation is positioned on theWIDE side or the TELE side with respect to the present PZ pulse. If theobjective PZ pulse is positioned on the WIDE side, bit 7 is set, and ifit is positioned on the TELE side, bit 6 is set. If the objective PZpulse is between the WIDE side and TELE side, neither bit 6 nor 7 isset.

Bits 3 through 5 indicate, by 1/8 segments, an approximate value whichis the difference between the objective PZ pulse number and the pulsenumber of the present position, i.e., PZ pulse number required for thelens to move from the present position to the objective position,divided by the total PZ pulse number (i.e., PZ pulse number required forthe lens to move from the WIDE end to the TELE end). Bits 3, 4 and 5 areweighted by 1/8, 1/4 and 1/2, respectively. The above value will be zerowhen the present position is equal to the objective position. Thus, bits3 through 5 are all cleared. If the present position is at the WIDE endand the objective position is at the TELE end, or vice versa, the valuewill be 7/8 and therefore bits 3 through 5 are all set at "1".

Thus, the camera body 11 receives, in LENS₋₋ INF1, periodically or uponrequest, information from the photographing lens 51 so that the camerabody is able to send appropriate ISZ control information to thephotographing lens 51.

The process checks if the operation based on predictor amount iseffective (F₋₋ PREOK=1). If effective, an objective PZ pulse Dumber(PZPFPRE), obtained by using predictor amount, is stored in anaccumulator (ACC). If not effective, an objective PZ pulse number (PZPF)obtained on the basis of the present AF pulse number is stored in theaccumulator (S523, S525, S527).

Then, the values of bits 3 through 7 in LENS₋₋ INF1 are calculated onthe basis of the objective PZ pulse number stored in the accumulator.The thus calculated values are stored in RAM 61b at a predeterminedaddress (i.e., bits 3 through 7 of LENS₋₋ INF1) and an interruptioninhibition operation (SEI) is performed (S529, S531).

When all of the following conditions are satisfied, that is, when theconstant image magnification zoom mode (Image Size Tracking Mode) isselected, the lens CPU correctly recognizes the current position (focallength) of the zoom lens group 53Z (F₋₋ PZPOS=1), and the zooming isbeing effected at the constant image magnification mode (F₋₋ ISOK=1),the following operations are effected. If any one of the conditions isnot satisfied, control skips to step S551 (steps S533-S537).

If operation of the objective focal length based on the predictor amount(PZ pulse number) is effective (flag F₋₋ FPREOK=1), and a control flagfor ISZ is set up (flag F₋₋ ISZD=1), the PZ pulse number obtained byusing the predictor amount (from equation 11)) is stored in RAM 61b at apredetermined address (PZPTRGT) as objective pulse number (S539, S541,S543). If, however, operation of the objective focal length based on thepredictor amount is not effective (F₋₋ FPREOK=0) or the ISZ control flagis cleared, PZ pulse number obtained on the basis of the AF pulse of thepresent position (advancement pulse number) using equation 12) is storedin the above predetermined address (PZPTRGT) in S539, S541 and S545.Flag F₋₋ ISZD is data which is sent from the camera body 11 by means ofcommunication and stored in RAM 61b. If F₋₋ ISZD=1, ISZ control isperformed on the basis of the calculated value based on the predictoramount. If flag F₋₋ ISZD=0, ISZ control is performed on the basis of thecalculated value based of the AF pulse of the present position.

Zoom speed data (bit 6, 7 of BD₋₋ ST1) sent from the camera body 11, andstored in RAM 61b, is stored in RAM 61b at apredetermined address (bit2, 3 of SPDDRC2). Constant image magnification ratio zooming flag F₋₋ISZ is set up and interruption is permitted. Then the operation isreturned (S547, S549, S551). Constant image magnification ratio flag F₋₋ISZ indicates that the CPU 61 has completed calculating the distance ofthe target focusing point, and that preparations for the motor and thezoom lens to be driven have been made. When the constant imagemagnification ratio flag F₋₋ ISZ has been set, a constant imagemagnification ratio zooming operation is performed in the 2 ms timerinterruption routine. The values of PZPTRGT, SPDDRC2 are also used inthe 2 ms timer interruption routine.

INSTRUCTION OPERATION

An instruction operation to be performed in the photographing lens 51when instruction codes (command) are received from the camera body 11will be explained below with reference to flow charts shown in FIGS. 19to 26, together with Tables 1 and 2 indicating the content of theinstruction codes. The instruction codes are details of S217 in thecommunication interruption routine of FIG. 8. Each instruction operationis performed depending upon the lower bits of the command.

A STANDBY command is a command to cause the lens CPU 61 to be broughtinto a low power (or sleep) mode. A flow chart regarding an operationupon input of the STANDBY command is shown in FIG. 19.

The lens CPU 61, upon receipt of the STANDBY command, sets up flag F₋₋STNDBY, transmits a command receipt completion command to the camerabody 11, allows communication interruption and is returned (S601, S602,S603). Lens CPU 61 checks flag F₋₋ STNDBY in the main routine at stepS143. If flag F₋₋ STNDBY is set up, the lens CPU stops the clock 91 andis transferred into a low power consumption mode (standby mode) (SeeFIG. 7).

An AF-INITPOS command is a command which is sent after the camera body11 has moved the focusing lens 53F to infinite end by means of the AFmotor 39. This command is an initializing operation command for AF toclear an AF pulse counter of the photographing lens 51. A flow chartregarding an operation performed by the lens CPU 61 when an AF-INITPOScommand is inputted is shown in FIG. 20.

Lens CPU 61, when an AF-INITPOS command is input, inputs distance codedata from distance code plate 81 (S611). If the code data corresponds tothe infinite end (far end), AF pulse present position data (AFPXL, H) inRAM 61b and AF pulse start position data (AFPSTRTL, H) are cleared. Aflag to identify that the present position of focusing lens 53F is knownF₋₋ AFPOS is set up and the process proceeds to S615. If the code datadoes not correspond to the infinite end, the process skips through theabove step and proceeds to S615. The process outputs command receiptcompletion command to body 11, allows communication interruption and isreturned (S615, S616).

A PZ-INITPOS command is a command which causes the lens CPU 61 toperform an initialization operation so as to identify the zoomingposition. In this embodiment, the PZ pulse number corresponding to thecode of the zoom code plate 71 is set in the PZ pulse counter when thezoom motor 65 is actuated, to detect the boundary 72 of the code of thezoom code plate 71. A flow chart regarding an operation performed when aPZ-INITPOS command is input is shown in FIG. 21. Operations such ascounting of the PZ pulse will be explained later in a POS-NG OPERATIONshown in FIG. 86.

Lens CPU 61, when a PZ-INITPOS command is input, clears flag F₋₋ PZPOS,sets up flags F₋₋ LBATREQ, F₋₋ IPZB and F₋₋ MOV, stores a predetermineddata (lowest speed, direction TELE) in lens RAM 61b at SPDDRC1, and setsPZPA2B of the PZ pulse counter to zero, the PZ pulse counter counting PZpulse from the present position to the code boundary (S621-S624). Theprocess outputs a command receipt completion signal, allowscommunication interruption and is returned (S625-S626). The initializingoperation regarding power zooming (PZ) is performed on the basis of theabove set value during the 2 ms timer interruption operation.

A RETRACT-PZ command is a command which effects power zooming of thephotographing lens 51 to minimize the length of the photographing lensbarrel (i.e., retract) when, for example, the main switch of the camerabody is turned off. A flow chart regarding an operation upon input ofthe RETRACT-PZ command is shown in FIG. 22.

Lens CPU 61, upon receipt of the RETRACT-PZ command, stores presentfocal length data in RAM 61b at a predetermined address (RETPOS L,H),sets the PZ pulse data by which the length of the lens barrel becomesminimum (data inherent to the lens) in RAM 61b at a predeterminedaddress, and sets predetermined data (maximum speed) in SPDDRC2 (S631,S632, S632-2). The Lens CPU also sets each flag F₋₋ LBATREQ, F₋₋ IPZBand flag F₋₋ MOVTRG, sends a command receipt completion signal, andpermits communication interruption. The process is then returned(S634-S636).

The focal length data before retraction (accommodation) is sent to thecamera body 11 by means of a separate communication command (FOCALLEN-X)which will be explained hereinafter. Flag F₋₋ LBATREQ is a flag whichasks for electricity supply to the power zoom lens 51 for the powerzooming operation thereof, flag F₋₋ IPZB is a flag which indicates thatzooming control (ISZ, PZ-INITPOS, etc.) is being conducted in the lens,and flag F₋₋ MOVTRG is a flag which moves zooming lens 53Z to anobjective pulse position stored in address PZPTRG in the 2 ms timerinterruption operation. The accommodation operation regarding thezooming lens 53Z is performed in the 2 ms timer interruption routine onthe basis of the above set value.

RET-PZPOS is a command for returning the zooming lens, from itsretracted state, to the state before it was retracted. In other words,it is a command to return the zooming lens 53Z to its state beforeretraction or accommodation, for instance, when the main switch of thecamera body SWMAIN is turned ON (to the position of with focal lengthbefore retract power zooming was performed). A flow chart showing anoperation upon input of the RET-PZPOS command is shown in FIG. 23.

When the lens CPU 61 receives the RET-PZPOS command, the lens CPU 61sets the focal length data, which is one of the data items stored in theaddress before retraction, designated by the code of the command andwhich is sent immediately before retract power zooming, at apredetermined address (FCLL, H) of the lens RAM 61b (S641). It should benoted that focal length data stored before retraction and sent from thecamera body 11 by means of a separate communication command is stored inthe address RETPOSL, H.

The above focal length data is converted into an objective pulse numberand stored in RAM 61b at a predetermined address as objective pulsenumber PZPTRG. A predetermined PZ speed data (high speed) is stored inSPDDRC2. Flags F₋₋ LBATREQ, F₋₋ IPZB, F₋₋ MOVTRG are then set and thecommand receipt completion signal is transmitted and communicationinterruption is permitted. The process is then returned (S642-S646). Itis noted that the return operation is also performed in the 2 ms timerinterruption operation.

IPZ-STOP is a command which stops the power zooming operation. Thiscommand is a command which stops controlled power zooming such as ISZ(constant image magnification), PZ-INITPOS (return), RETRACT-PZ(retraction or accommodation). It is not a command to stop manual powerzooming. A flow chart regarding an operation upon input of the IPZ-STOPcommand is shown in FIG. 24.

Lens CPU 61, when the IPZ-STOP command has been inputted, clears flagF₋₋ ISOK, together with flags (F₋₋ MOVTARG, F₋₋ MOV, F₋₋ ISZ). regardingthe performance of the power zooming operation (S651, S652). F₋₋ ISZdesignates the flag that indicates drive of the power zoom motor in theISZ mode. Lens CPU 61 outputs a command receipt completion signal andpermits communication interruption and the process is then returned(S653, S654). Since the above flags are cleared, controlled powerzooming such as ISZ (i.e., other than manual power zooming) is notperformed in the 2 ms timer interruption operation.

ISZ-MEMORY is a command which stores present values of AF pulse andfocal length in order to perform constant image magnification zooming. Aflow chart regarding an operation upon input of ISZ-MEMORY command isshown in FIG. 25.

When an ISZ-MEMORY command is inputted, lens CPU 61 stores the presentvalue (AFPXL,H) of the AF pulse counter in ISZAF pulse memory (ISZ₋₋AFPL,H) in lens RAM 61b at a predetermined address. Lens CPU 61 alsostores the present value (FCLXL,H) of the focal length in ISZ focallength memory (ISZ₋₋ FCLL,H) in lens RAM 61b at a predetermined addressin steps S661, S662. Flag F₋₋ ISZM is the set, a command receiptcompletion command is outputted, and communication interruption ispermitted. The process is then returned (S663-S665). On the basis of theabove values, the operation of ISZ indicated by S465-S475 in FIG. 15 isperformed.

ISZ-START is a command which starts constant image magnificationzooming. A flow chart regarding an operation upon input of the ISZ-STARTcommand is shown in FIG. 26.

When the ISZ-START command is inputted, lens CPU 61 sets flags F₋₋LBATREQ, F₋₋ IPZB, F₋₋ ISOK and outputs a data transmission completionsignal. Communication interruption is permitted and the process isreturned (S671-S673). On the basis of the above values, the 2 ms timerinterruption operation and operations at and after S537 in FIG. 18 willbe performed.

BL COMMAND SUBROUTINE

The operation in the photographing lens 51 upon receipt of a BL commandfrom camera body 11 will be explained with reference to FIGS. 27 to 37.The BL command communication operation is similar to that performed inthe instruction command subroutine, except that the command receiptcompletion signal is first outputted, then data is inputted, and theinputted completion signal is outputted. The BL command is a detail ofS213 in the communication interruption subroutine of FIG. 8. Eachcommand operation is performed depending upon the content of lower bitsof the command.

PZ-BSTATE (20) is a command which sends necessary data for IPZ (constantimage magnification ratio zooming). The data sent by this commandincludes data which indicates the status of the focusing lens 53F, i.e.,whether the lens is at the far end (infinite end) (F₋₋ ENDF=1) or thenear end (closest end (F₋₋ ENDN=1), in far move (F₋₋ FARM=1) or nearmove (F₋₋ NEARM=1), whether or not the lens is in overlap integration(F₋₋ OVAF=1), whether or not it is in a moving object prediction mode(F₋₋ MOBJ=1), whether or not it is in a focusing state (F₋₋ AFIF=1),whether an image magnification ratio should be stored by means ofcommand (communication) from the body or by means of judgement by thelens CPU 61 (F₋₋ ISM=1), etc. A flow chart regarding an operation uponreceipt of the PZ-BSTATE command is shown in FIG. 27.

When the PZ-BSTATE command is inputted, the lens CPU 61 sends a commandreceipt completion signal, inputs PZ-BSTATE data of 1 byte from camerabody 11, and performs subroutine CNTAFP regarding an AF pulse countoperation (S701-S703). Detail of the CNTAFP subroutine is shown in FIGS.39 to 43 which will be explained hereinafter.

A data input completion signal is then outputted and communicationinterruption is permitted. Then, the process is returned (S704, S705).The camera has an AF drive source mounted to the body 11. Accordingly,when AF pulses are counted in the lens 51, driving direction informationof AF, etc. is always sent from the body 11 to lens 51 by means of thiscommand, before actuating AF and after changing driving direction.

BODY-STATE0 is a command which informs the photographing lens of dataregarding the state or condition of the body. This command is sentduring periodical communication between the photographing lens and thecamera body. A flow chart regarding an operation upon receipt of theBODY-STATE0 command is shown in FIG. 28.

When the BODY-STATE0 command is inputted, the lens CPU 61 sends acommand receipt completion signal, and inputs data (BODY-STATE0) of 1byte regarding the status of the body 11 from the body so as to storethe data in lens RAM 61 at BD₋₋ ST0 (S711-S713). When the upper 5 bitsof the above 1 byte data are masked and stored in lens RAM 61b at ZM₋₋MODE, a data input completion signal is outputted and communicationinterruption is permitted. The process is then returned (S714-S716).

In the lower 3 bits, BODY-STATE0 data includes information regarding thepower zooming mode of the camera body 11, such as, constant imagemagnification ratio (ISZ), during-exposure zooming (EXZ), manual powerzooming (MPZ), etc. BODY-STATE0 data includes, in the upper 5 bits,information regarding the ON/OFF status of an electric source of thebody circuit system (F₋₋ VDD=1), the ON/OFF status of the photometricswitch (F₋₋ SWS=0), supply of electricity from the body 11 to the zoommotor (F₋₋ BATT=1), AF/MF changing switch of the body 11 being AF or MF(F₋₋ SWAF), and the mode of AF being single or continuous (F₋₋ MAF).Note that the flag F₋₋ SWAF which indicates the switch data of the AF/MFselecting switch provided in the camera body indicates AF and MF whenthe flag is set and cleared, respectively.

Flag F₋₋ BATT is set on the camera body side by the main CPU 35 whenelectricity is supplied to the terminal VBATT. On the other hand, on thelens side, the lens CPU 61 monitors the level of voltage of the terminalVBATT through the port P12. The lens CPU 61 sets the flag F₋₋ BDET forthe detection of the electric source of the power zooming being turnedON when the voltage is over a predetermined level. Then, the flag F₋₋BDET is outputted to the body side (in the main CPU) by the POFF-STATEcommunication. The camera body can determine if electric power isproperly supplied to the lens side by checking if flag F₋₋ BDET is set.

When the flag F₋₋ BDET remains cleared even if the flag F₋₋ BATT hasbeen set, the power supply to the terminal VBATT is stopped on theassumption that something unusual has occurred.

BODY-STATE1 is a command which sends data regarding the status of thecamera body 11, similar to those in BODY-STATE0 command. This commandincludes information regarding the status of the sequence of operationsof the camera body 11. A flow chart regarding an operation upon receiptof a BODY-STATE1 command is shown in FIG. 29.

Upon receipt of the BODY-STATE1 command, the lens CPU 61 sends a commandreceipt completion signal and inputs data (BODY-STATE1) of 1 byte fromthe body 11 so as to store them in the lens RAM 61b at BD₋₋ ST1(S721-S723). If flag F₋₋ IPZD is set, flags F₋₋ ISOK, together withflags F₋₋ MOVTRG, F₋₋ MOV, F₋₋ ISZ of address BD₋₋ ST1 are cleared. Ifflag F₋₋ IPZD is not set, the above operation is not performed (S724,S725, S726). A data input completion signal is outputted, and thencommunication interruption is permitted. Finally, the process isreturned (S724, S727, S728).

The operation to be performed when flag F₋₋ IPZD is set is an operationsimilar to the IPZ-STOP command of instruction code 35. This commandcauses the lens CPU 61 to receive information regarding the body and toperform an IPZ-STOP command. Flags relating to the command will beexplained below.

F₋₋ IPZD is a flag which identifies whether or not an operation similarto IPZ-STOP is to be performed.

F₋₋ MPZD is a flag which identifies whether or not manual power zoomingis to be inhibited. When F₋₋ MPZD is set, manual power zooming isinhibited. Flag F₋₋ MPZD is referred to during the 2 ms timerinterruption operation.

F₋₋ ISZD is a flag which identifies whether or not ISZ is to becontrolled on the basis of AF pulse number of the present position(during focusing) or on the basis of focal length obtained from apredictor amount. This flag is referred to during a subroutine of ISZ(S541 in FIG. 18).

F₋₋ ISSPA and F₋₋ ISSPB are flags which identify the control speed ofISZ and are referred to in S547 in FIG. 18.

A flow chart regarding an operation upon receipt of a SET-AFPOINTcommand is shown in FIG. 30.

Lens CPU 61 inputs a SET-AFPOINT command (23), outputs a command receiptcompletion signal, receives SET-AFPOINT data of 1 byte from the bodyside, so as to set them in lens RAM 61b at a predetermined address,outputs a data input completion signal and permits communicationinterruption. The process is then returned (S731-S735).

The SET-AFPOINT command is performed before communication of the LBcommand and LENS-AFPULSE (15).

A LENS-AFPULSE command determines which AFPULSE is to be sent from lens51 to body 11, depending upon information sent by the SET-AFPOINTcommand.

When bit 3 (X) is set, AF pulse (AFPULSE (AFPXL,H)) of the presentposition is sent.

When bit 7 (ISZM) is set, AF pulse number (AFPULSE (ISZ₋₋ AFPL,H)),obtained when image magnification ratio is stored during ISZ mode, issent. It is to be noted that it is impossible for bit 3 and bit 7 to beset at the same time.

If neither bit 3 nor bit 7 is set, bits 4 through 6 (FM0, FM1, FM2)become effective.

8 segments (0-7) for memorizing AF pulse data are provided in the lensRAM 61b of lens CPU 61 (AFPOL,H AFP7L,H). AF pulse data may be stored inrespective segments by means of a command from the camera body 11. Thethree bits of bits 4 through 6 designate addresses 0 to 7. AF pulse datamemorized in such addresses will be transmitted. This command onlyserves to designate one of the AF pulse data to be sent to the body 11in LENS-AFPULSE (15).

A flow chart regarding an operation upon receipt of a SET-PZPOINTcommand is shown in FIG. 31.

When a SET-PZPOINT command (24) is inputted, the lens CPU 61 outputs acommand receipt completion signal, receives SET-PZPOINT data from thebody side and sets the same in the lens RAM 61b at a predeterminedaddress, outputs a data input completion signal, and permitscommunication interruption. The process is then returned (S741-S745).

The SET-AFPOINT command is performed before communication of the LBcommand and FOCALLEN-X (16).

The LENS-AFPULSE command determines, on the basis of information sent bySET-PZPOINT command, whether focal length data of the present positionor the focal length obtained when the image magnification ratio ismemorized during the ISZ mode is to be sent to the camera body 11.

When bit 3 (X) is set, focal length data (FCLXL,H) of the presentposition is sent.

When bit 7 (ISZM) is set, focal length (focal length (ISZ₋₋ FCLL,H) ofISZ memory) obtained when the image magnification ratio is stored duringISZ mode is sent. It is to be noted that it is impossible for bit 3 andbit 7 to be set at the same time.

When neither bit 3 nor bit 7 is set, bits 4 through 6 (FM0, FM1, FM2)become effective.

8 segments (0-7) for memorizing focal length are provided in lens RAM61b (FCL0L,H-FCL7L,H). Focal length may be stored in respective segmentsby means of a SET-PZPOINT command from the body 11. Three bits of bits 4through 6 designate addresses 0 to 7. The focal lengths memorized insuch addresses will be transmitted. This command only serves todesignate one of the focal lengths to be sent to the body 11 inFOCALLEN-X (16).

STORE is a command which sets predetermined AF pulse data at adesignated address. A flow chart regarding an operation upon receipt ofa STORE-AFP command is shown in FIG. 32.

Lens CPU 61, upon receipt of a STORE-AF command (25), outputs a commandreceipt completion signal and inputs data of 2 bytes from the camerabody 11 (S751, S752). If one of the bits is not ISZ memory (ISZM=0), theinput data is stored in lens RAM 61b at address (AFP0L,H-AFP7L,H),designated by AM0-AM2 of the data. The data is otherwise (ISZM=1) storedin the ISZ memory (ISZ-AFPL,H) of lens RAM 61b (S751-S756). ISZoperational flag F₋₋ ISZXOM is set, data input completion signal isoutputted, and communication interruption is permitted. The process isthen returned (S757-S758).

STORE-DEFP&D (26) is a command which causes the lens RAM 61b to storedefocus amount and defocus pulse regarding camera body 11. A flow chartregarding an operation upon receipt of the STORE-DEFP&D command is shownin FIG. 33.

Lens CPU 61, upon receipt of a STORE-DEFP&D command, outputs a commandinput completion signal, and inputs defocus pulse data of 2 bytes anddefocus amount data of 2 bytes from the camera body 11. This inputteddefocus pulse is multiplied by 1/2 (S761-S764) in this case. Since theratio of body AF pulses to lens AF pulses is 2:1, the input defocuspulse is multiplied by 1/2, although the ratio may be set as desired.

If flag F₋₋ SIGN has been cleared, the defocus pulse number is added tothe present AF pulse number so as to store the added value in ISZ₋₋ FPX.If flag F₋₋ SIGN has not been cleared, the defocus pulse number issubtracted from the present AF pulse number and the subtracted value isstored in ISZ₋₋ FPX. When flag F₋₋ SIGN=1, the defocus amount is towardthe FAR end, and when F₋₋ SIGN=0, the defocus amount is toward the NEARend. Then, flag F₋₋ FPRE is set, a data input completion signal isoutputted, and communication interruption is permitted. The process isthen returned (S765-S771). The defocus pulse transmitted by means of thecommunication as described above is used in the ISZ operation routine soas to obtain objective focal length by utilizing defocus pulse. Flag F₋₋FPRE is a flag which gives an indication to perform an operation using apredictor amount.

STORE-PZP (27) is a command which causes the present AF position(position of the focusing lens or the focusing object distance) andpresent position of PZ (position of the group of zooming lenses 53Z orthe focal length) to be stored in a designated memory (address).

STORE-PZF is a command which causes the focal length designated by thecamera body 11 to be stored at a predetermined address.

A flow chart regarding an operation upon receipt of the STORE-PZPcommand is shown in FIG. 34.

Lens CPU 61, upon receipt of the STORE-PZP command, outputs a commandreceipt completion signal and inputs data of 1 byte from the camera body11 (S781, S782). If the PZ memory is designated (when PZM flag is set),focal length data of the present position is stored in the address(FCL0L,H-FCL7L,H) designated by FM0-FM2, otherwise the focal length datais not stored (S783, S784).

If the AF memory is designated (when AFM flag is set), an AF pulsenumber of the present position is stored in the address(AFP0L,H-AFP7L,H) designated by AM0-AM2. Otherwise, a data inputcompletion signal is simply outputted, while permitting communicationinterruption. The process is then returned (S785-S788).

A flow chart regarding an operation upon receipt of a STORE-PZF commandis shown in FIG. 35.

Lens CPU 61, upon receipt of a STORE-PZF command, inputs data of 2 bytesfrom the camera body. If this command is not ISZ memory (if flag F₋₋ISZFM is not set), the inputted data of 2 bytes are stored in lens RAM61b at address (FCL0L,H-FCL7L,H) designated by bits FM0 FM2. If thecommand is ISZ memory (if flag F₋₋ ISZFM is set), the inputted data isstored in ISZ memory and a flag F₋₋ ISZFOM, which performs operation onthe basis of focal length, is set up (S791-S796). The a data inputcompletion signal is outputted and communication interruption ispermitted. The process is then returned (S797-S798).

STORE-IS (29) is a command which causes the image magnification ratiomemory (address ISZ-IMGL,H of lens RAM 61b) to store an imagemagnification ratio. A flow chart regarding an operation upon receipt ofthe STORE-IS command is shown in FIG. 36.

Lens CPU 61, upon receipt of the STORE-IS command, outputs a commandreceipt completion signal, inputs data of 2 bytes regarding an imagemagnification ratio from the camera body 11, stores the data in an imagemagnification ratio memory (ISZ-IMGL,H), and sets flag F₋₋ STIS(S801-S804). The data input completion signal is outputted andcommunication interruption is permitted. The process is then returned(S805-S806). Flag F₋₋ STIS is a flag for performing an operation ofimage magnification constant zooming in accordance with the imagemagnification ratio sent from the camera body.

MOVE-PZMD (2A) is a command which causes power zooming in the designateddirection or toward a focal length in the designated memory (address inlens RAM 61b).

MOVE-PZF (2B) is a command which performs power zooming to a designatedfocal length, for example, to a focal length calculated in the camerabody 11. The data of this command includes data regarding focal lengthand zooming speed.

A flow chart regarding an operation upon receipt of the MOVE-PZMDcommand is shown in FIG. 37.

Lens CPU 61, when the MOVE-PZMD command is inputted, outputs a commandinput completion signal, and inputs data of 1 byte from the camera body11 (S811-S812). If the flag F₋₋ MDM is set in the input data, data isread out from the address (FCL0L,H-FCL7L,H) designated by MVM0-MVM2. Theread out data is converted into PZ pulse data and stored in the lens RAM61b at PZPTRGT. Driving speed data (F₋₋ SPA, F₋₋ SPB of bits 6 and 7) isstored in SPDDRC2, and flag F₋₋ MOVTRG is set. If flag F₋₋ MDM is notset, the upper 4 bits of the input data are stored in address SPDDRC1and flag F₋₋ MOV is set (S813-S819). These data are referred to in the 2ms timer interruption routine so as to perform power zooming in adesignated manner.

When flags F₋₋ LBATREQ and F₋₋ IPZB are set, a data input completionsignal is outputted and communication interruption is permitted. Theprocess is then returned (S820-S820-3). If flag F₋₋ MDM (bit 3) is set,the command is to perform power zooming toward the focal length storedin the designated memory. If flag F₋₋ MDM is not set, the command is toperform power zooming in a direction designated by flag F₋₋ MDT and F₋₋MDW (bits 4 and 5). Flag F₋₋ MDT designates driving in the TELEdirection, flag F₋₋ MDW designates driving in the WIDE direction, andflags F₋₋ SPA and F₋₋ SPB (bits 6 and 7) designate zooming speed.

A flow chart regarding an operation upon receipt of a MOVE-PZF commandis shown in FIG. 38.

Lens CPU 61, when the MOVE-PZF command is inputted, outputs a commandreceipt completion signal, inputs focal length data of 2 bytes fromcamera body 11, converts input focal length data into PZ pulse data soas to store the same in the lens RAM 61b at address PZPTRGT, sets speeddata in SPDDRC2, and sets flags F₋₋ LBATREQ, F₋₋ IPZB, F₋₋ MOVTRG. Thesedata are referred to in the 2 ms timer interruption routine so as toperform power zooming in a designated manner. A data input completionsignal is outputted and communication interruption is permitted. Theprocess is then returned (S821-S827).

CNTAFP OPERATION

An AF pulse count operation in the photographing lens 51 will beexplained below with reference to the flow charts shown in FIGS. 39 to43. This count operation is a detail of an operation executed in S703 bymeans of the PZ-BSTATE command (20) shown in FIG. 27. In the illustratedembodiment, the value of the AF pulse counter is cleared (set to zero)when the focusing lens 53F reaches the FAR end (infinite photographingposition). On the other hand, a maximum value is set at the AF pulsecounter when the focusing lens reaches the NEAR end (closestphotographing position). In the case of NEAR MOVE (driven toward closestdistance), the AF pulse outputted from AF pulser 59 is added thereto. Inthe case of FAR MOVE (driven toward infinite), the AF pulse issubtracted therefrom.

Interruption is inhibited, the data inputted during communication isstored at address PZ₋₋ BDST, and the present distance code is inputtedfrom the distance code plate 81 (S901-S905).

If the flag F₋₋ ENDF to identify FAR END (infinite position) is set, itis checked if the inputted distance code is a code of the FAR END(S907-S909). If the distance code is FAR END, the present AF pulse valueand AF pulse count start value (address AFPZL,H, AFPSTRTL,H) are clearedand a flag F₋₋ AFPOS is set up to indicate that the AF pulse of thepresent position is known (S909, S913, S915). If a flag F₋₋ NEARM toidentify NEAR MOVE is cleared, the process jumps to a CNTAFP10operation. If F₋₋ NEARM flag is set, the process jumps to a CNTAFP11operation, since the driving direction is to be changed (S917). If thedetected distance code is not the FAR END code, far end flag F₋₋ ENDF iscleared and the process jumps to a CNTAFP3 operation (S909 and S911).

If the far end flag F₋₋ ENDF is cleared, the near end flag F₋₋ ENDN,which identifies the near end (closest focusing position), is checked.If the near end flag is cleared, the process proceeds to CNTAFP3 (S919).

If the near end flag F₋₋ ENDN is set, the process checks if the distancecode is the near end code. If it is not the near end code, the near endflag F₋₋ ENDN is cleared and the process proceeds to a CNTAFP3 operation(S919-S923). If the distance code is the near end, the AF pulse countvalue and AF pulse count start value are set at a maximum (set N₋₋AFMAXL,H at AFPXL,H, AFPSTRTL,H), and flag F₋₋ AFPOS which identifiesthat the present AF pulse is known is set. The process checks if thepresent status is FAR MOVE (F₋₋ FARM=1). If it is FAR MOVE, the processproceeds to a CNTAFP11 operation, otherwise the process proceeds to aCNTAFP10 operation (S925-S929).

As described above, in the case of FAR END (F₋₋ ENDF=1) or NEAR END (F₋₋ENDN=1), the count value of the AF pulse is corrected by thecorresponding predetermined value. If the input distance code isdetermined to be at neither end, the above end point correction is notperformed.

An operation (CNTAFP3 operation) when the group of focusing lenses 53Fis positioned between the FAR END and NEAR END will be explained withreference to a flow chart shown in FIG. 40.

First, a counter value, in a hard counter of the present AF pulse, isset in an AF pulse counter (AFPCNTL,H) in steps S931, S933. If flag F₋₋FARM is cleared, the process proceeds to a CNTAF6 operation. If F₋₋ FARMflag is set, it is checked if the previous status was NEAR MOVE (i.e.,if flag F₋₋ NEARM0 is set) in steps S933, S935. If it is determined thatthe status has been changed from NEAR MOVE to FAR MOVE, an AF pulsecount start value (AFPCNTL,H) is added to an AF pulse counter startvalue (AFPSTRL,H) so as to store it in the AFPXL, H & AFPSTRTL, H memoryfor present AF pulse value and AF pulse count start value. The processthen proceeds to a CNTAFP12 operation (S935, S937).

If the previous status was not NEAR MOVE, it is determined if theprevious status was FAR MOVE. If it is not the FAR MOVE, i.e., the lenswas not moved, the process proceeds to CNTAFP11. If the previous statuswas also FAR MOVE, a count value (AFPCNTL,H) is subtracted from the AFpulse count start value (AFPSTRL,H) so as to store the difference in thepresent AF pulse value (AFPXL,H), since there is no change in drivingdirection. Then, the process proceeds to a CNTAFP6 operation (S939,S941).

The CNTAFP6 operation, when the present status is not FAR MOVE, will beexplained below with reference to the flow chart shown in FIG. 41. It isnoted that the CNTAFP6 operation is the first operation that the processenters after start-up.

The process checks if the status is NEAR MOVE. If it is not NEAR MOVE,the process proceeds to a CNTAFP8 operation (S951). If it is NEAR MOVE,the process checks if the previous status was NEAR MOVE. If the previousstatus was also NEAR MOVE, an AF pulse count value (AFPCNTL, H) is addedto the AF pulse count start value (AFPSTRTL,H) so as to store the sum asthe present AF pulse value (AFPXL,H) in steps S953, S955.

If the previous status was not NEAR MOVE, but rather is FAR MOVE, thisis an indication that the driving direction is to be changed.Accordingly, the AF count value (AFPCNTL,H) is subtracted from the AFpulse count start value (AFPSTRTL,H) so as to store the difference inthe AF pulse value and AF pulse count start value (AFPXL,H&AFPSTRTL,H)in steps S958, S959. If the status is not FAR MOVE, the process proceedsto a CNTAFP11 operation (S957).

An operation effective upon stopping of the AF motor (CNTAFP8 OPERATION)will be explained below with reference to a flow chart shown in FIG. 42.

In the CNTAFP8 operation, the process first checks if the previousstatus was NEAR MOVE (S961).

If the previous status was NEAR MOVE, this means that the lens wasstopped during NEAR MOVE. Accordingly, an AF pulse count value(AFPCNTL,H) is added to the AF pulse count start value (AFPSTRTL,H) andthe sum is stored in the AF pulse value and AF pulse count start value(AFPXL,H & AFPSTRTL,H). The process then proceeds to a CNTAFP10operation (S961, S963).

If the previous status was FAR MOVE, this means that the lens wasstopped during FAR MOVE. Accordingly, an AF pulse count value(AFPCNTL,H) is subtracted from the AF pulse count start value(AFPSTRTL,H) so as to store the difference as the present AF pulse valueand AF pulse count start value (AFPXL,H & AFPSTRTL,H). The process thenproceeds to a CNTAFP10 operation (S961, S965, S967).

If the previous status was not NEAR MOVE nor FAR MOVE, this means thatthe lens has been stopped. Accordingly, the process proceeds to aCNTAFP16 operation (S961, S965).

CNTAFP10, 11, 12, 16 operations will be explained below with referenceto the flow chart shown in FIG. 43.

The process enters a CNTAFP10 operation just after the AF motor 39 hasstopped. Accordingly, the LED of the AF pulser 59 is turned off, thecontent of PZ₋₋ BDST is stored in PZ₋₋ BDST0, and communicationinterruption is permitted. The process then passes through the AF pulsecount operation (S971, S977, S979).

The process enters a CNTAFP11 operation upon start of AF driving.Accordingly, the LED of AF pulser 59 is turned on, AF pulse hard counterand AF pulse count value memory (AFPCNTL,H) are cleared, the content ofPZ₋₋ BDST memory is transferred to PZ₋₋ BDST0, and communicationinterruption is permitted. The process then passes through an AF pulsecount operation (S973, S975, S977, S979).

The process enters a CNTAFP12 operation when the driving direction ischanged during the actuation of AF. Accordingly, the AF pulse hardcounter and AF pulse count value (AFPCNTL,H) are cleared, the content ofPZ₋₋ BDST memory is transferred to PZ₋₋ BDST0, and communicationinterruption is permitted. The process then passes through an AF pulsecount operation (S975, S977, S979).

The process enters a CNTAFP16 operation or processing during movement inthe direction of NEAR MOVE or FAR MOVE (S655, S641), or when the AFmotor is stopping (S965). Accordingly, the content of PZ₋₋ BDST istransferred to PZ₋₋ BDST0 and communication interruption is permitted.The process then passes through the AF pulse count operation (S977,S979).

LB COMMAND OPERATION

An operation regarding a command which has the power zoom lens 51 sendthe information of the lens, i.e., state of the lens, to the camerabody, in accordance with a demand from the camera body, will beexplained below with reference to table 4 and the flow charts shown inFIGS. 44 to 51. Content of the command is shown in Table 4. The flowcharts shown in FIGS. 44 to 51 are details of an operation of S209 in acommunication interruption routine shown in FIG. 8. An operation will beperformed in accordance with the lower bits of the command.

PZ-LSTATE OPERATION

The flow chart shown in FIG. 44 illustrates a PZ-LSTATE (10) command bywhich data regarding power zooming control of the power zoom lens 51 issent to the camera body 11. Lens CPU 61, upon receipt of a (PZ-LSTATE)command requiring lens state information regarding power zooming,outputs a command receipt completion signal and thereafter outputs dataregarding the type of power zooming control, (for example, constantimage magnification ratio zooming control) to the camera body 11 (S1001,S1002). A data input completion signal is outputted and communicationinterruption is permitted. The process is then returned (S1003, S1004).

Flags used in this operation will be explained below.

Flag F₋₋ TMOV (bit 0) is set when the zoom motor is moving in the TELEdirection.

Flag F₋₋ WMOV (bit 1) is set when the zoom motor is moving in the WIDEdirection.

Flag F₋₋ TEND is set when the group of zooming lenses 53Z is positionedat the TELE end.

Flag F₋₋ WEND is set when the group of zooming lenses 53Z is positionedat the WIDE end.

Flag F₋₋ IPZB is set when power zooming (initializing operation for ISZ,PZ, and retracting operation) is performed in a mode other than themanual power zooming.

Flag F₋₋ IPZI is set when manual power zooming is performed during anISZ operation.

Flag F₋₋ ISOK is set during an ISZ operation.

Flag F₋₋ MPZ is set while manual power zooming is being performed.

POFF-STATE, POFFS-WSLEEP OPERATION

FIG. 45 illustrates a flow chart regarding the POFF-STATE (11) operationand POFFS-WSLEEP (12) operation. These operations serve to send to thebody 11 information regarding power zooming of the lens, battery requestinformation, monitor information of the electric source (battery) forPz, etc. The difference between POFF-STATE (11) and POFFS-WSLEEP (12)resides in whether or not lens CPU 61 enters a lower power consumptionmode after completion of this command communication. When thePOFFS-WSLEEP (12) operation is performed, flag F₋₋ STNDBY is set duringthe communication and the lens CPU 61 proceeds to a low powerconsumption mode when returned to the main routine. That is to say,POFFS-WSLEEP (12) command is a command which performs both thePOFF-STATE (11) and STANDBY command (30) of the instruction code.

In the case of the POFFS-WSLEEP (12) command, the lens CPU 61 sets theflag F₋₋ STNDBY, outputs a command receipt completion signal, and inputsthe condition of switches (75, 77). If flag F₋₋ STNDBY is set (in thecase of POFFS-WSLEEP (12)), electrically driven/manual changing switch(D/M switch) is assigned to an electrically driven mode. At this time,if the TELE or WIDE switch (speed changing switch) is turned on, theprocess sets the battery request flag F₋₋ BATREQ and proceeds to S1025.Otherwise, the process proceeds to S1025 (S1017, S1019, S1021, S1023).

If the flag F₋₋ STNDBY is set, the process normally completes thiscommunication interruption and proceeds to a low power consumption modeafter it is returned to the main routine. If, however, flag F₋₋ BATREQis set, the process does not proceed to a low power consumption mode sothat manual power zooming operation is possible, even though flag F₋₋STNDBY is set to perform the normal operation, (see FIG. 7).

When flag F₋₋ STNDBY is not set, the process will not proceed to a lowpower consumption mode, even though it is returned to the main routine.Accordingly, operations such as manual power zooming will be possibleeven if flag F₋₋ BATREQ is not set in this command, provided that PZspeed switch 75 is turned on.

The process will proceed directly to S1025 if flag F₋₋ STNDBY is cleared(when POFF-STATE(11)).

In S1025, flags F₋₋ SLSW, F₋₋ ASSW, F₋₋ PZM, F₋₋ PZD, F₋₋ AFSW are setor cleared, depending upon the data of the zoom mode changing switch 77.The state of the VBATT terminal is monitored and if electric power forPZ is not supplied from the camera body 11, flag F₋₋ BDET is cleared(VBATT OFF), otherwise flag F₋₋ BDET is set (VBATT ON) in stepsS1027-S1031. The data (POFF-ST) of 1 byte, as set above, is transmittedto the camera body 11, a data input completion signal is outputted andcommunication interruption is permitted. The process is then returned(S1033-S1037).

The flag F₋₋ SLSW indicates that the zoom setting button SL of the powerzoom lens 51 is made ON and OFF when the flag is set and cleared,respectively.

The flag F₋₋ ASSW indicates that the slide switch of the power zoom lens51 is in the position AS (i.e., self-back position or automatic powerzoom mode changing position) and the position P or A (i.e., not in theposition AS) when the flag is set and cleared, respectively.

The flag F₋₋ PZM indicates that the slide switch of the power zoom lens51 is in the position AS or A (i.e., auto-zoom position) and theposition P (i.e., manual power zoom position) when the flag is set andcleared, respectively.

The flag F-PZD on the power zoom lens side indicates that the switch ofthe power zoom lens 51 is a motor-driven switch and a manual switch whenthe flag is set and cleared, respectively.

The flag F₋₋ AFSW indicates that the AF switch of the power zoom lens 51is in the AF position and MF position when the flag is set and cleared,respectively.

When a POFF-STATE operation is performed, the process jumps to stepS1013 by-passing the flag F₋₋ STNDBY set operation in step S1011.Thereafter, operations similar to those of the POSFFS-WSLEEP operationwill be performed.

LENS-INF1 OPERATION

A flow chart of a LENS-INF1 command shown in FIG. 46 illustrates anoperation by which various information of the lens 51 is sent to thecamera body 11.

Lens CPU 61, upon input of a LENS-INF1 data request command, sends acommand receipt completion signal, clears 2 bits of LENS₋₋ INF1 data of1 byte relating to the direction of power zooming, sets 1 bit toidentify AE auto-lens, and inputs switch information of zoomingdirection (S1041-S1043). In response to the switch information as input,the corresponding bit is set so as to send 1 byte lens data to camerabody 11 (S1044, S1045). A data transmission completion signal isoutputted, and communication interruption is permitted. The process isthen returned (S1046 and S1047). It is to be noted that LENS₋₋ INF1 dataincludes data relating to constant image magnification ratio zooming.The detail of which is described above.

LENS-INF2 OPERATION

The flow chart of a LENS-INF2 command shown in FIG. 47 performs anoperation by which fixed data inherent to the lens 51 is sent to thecamera body 11.

Lens CPU 61, upon input of a LENS-INF2 command, outputs a commandreceipt completion signal, outputs LNS-INF2 data to the camera body 11,outputs a data input completion signal, and permits communicationinterruption. The process is then returned (S1051-S1054). LENS-INF2 dataincludes data to identify lens type, and PZ lens and the data is fixeddata stored in ROM 61a.

LENS-AFPULSE OPERATION

A flow chart of a LENS-AFPULSE command shown in FIG. 48 is for anoperation by which lens AF pulse count data is outputted to the camerabody 11.

As explained above, the SET-AFPOINT command communication is alwaysperformed prior to communication of the LENS-AFPULSE command. Thecontent of the SET-AFPOINT command determines the AF pulse which is tobe sent to the body by means of the LENS-AFPULSE command.

Lens CPU 61, upon input of the LENS-AFPULSE command, outputs a commandreceipt completion signal, and, if present AF pulse is required, storesthe present AF pulse number (AFPXL,H) in a register (S1061-S1063). Whena pulse of constant image magnification ratio zooming (ISZ9) isdemanded, AF pulse data (ISZ-AFPL,H) of ISZ is stored in the register(S1062, S1064, S1065). In a case other than the above two cases, AFpulse data (AFPOL,H-AFP7L,H) of designated address is stored in theregister (S1062, S1064, S1066). Thereafter, AF pulse data, set in theregister, is outputted to the camera body 11, a data transmissioncompletion signal is outputted, and communication interruption ispermitted. The process is then returned (S1067-S1069).

FOCALLEN-X OPERATION

A FOCALLEN-X command operation by which focal length data of the lens 51is outputted to the camera body 11 will be explained below withreference to a flow chart illustrated in FIG. 49.

As explained above, the SET-PZPOINT command communication is alwaysperformed prior to a FOCALLEN-X command communication. The SET-PZPOINTcommand determines a focal length which is to be sent to the body uponreceipt of the FOCALLEN-X command.

Lens CPU 61, upon receipt of the FOCALLEN-X command, outputs a commandreceipt completion signal, and stores the present focal length (FCLXL,H)in the register, if present focal length is required (S1071-S1073). Whena focal length (ISZ-FCLL,H) for constant image magnification ratiozooming (ISZ) is required, a focal length (ISZ-FCLL,H) for constantimage magnification ratio zooming is stored in the register (S1072,S1074, S1075). In a case other than the above two cases, a focal length(FCL0L,H-FCL7L,H) of designated address is stored in the register(S1072, S1074, S1076). The focal length data set in the register isoutputted to the camera body 11, a data transmission completion signalis outputted, and communication interruption is permitted. The processis then returned (S1077-S1079).

IMAGE-LSIZE OPERATION

A flow chart of an IMAGE-LSIZE command shown in FIG. 50 is for anoperation by which image magnification ratio data for performingconstant image magnification ratio zooming, stored in lens RAM 61b at apredetermined address, is sent to the camera body 11.

Lens CPU 61, upon input of an IMAGE-LSIZE command, outputs a commandreceipt completion signal to the camera body 11, outputs data(ISZ-IMGL,H) relating to image magnification ratio (image size) tocamera body 11, outputs a data transmission completion signal, andpermits communication interruption. The process is then returned(S1081-S1085).

16 BYTE DATA PROCESSING

A 16 byte data flow chart shown in FIG. 51 is for an operation by whichbasic lens data of 16 bytes are all sent to camera body 11. It is to benoted that this command is a detail of the operation performed in thecommunication interruption routine of FIG. 8 at S221. Depending upon thelower bits of the command, each command will be performed. Processing ofthe first half 8 bytes and second half 8 bytes are similar to that ofthe 16 byte data communication and hence a detailed explanation isomitted.

Lens CPU 61, upon input of a 16 byte command, outputs a command receiptcompletion signal to the camera body 11, outputs a predetermined data(LC0-LC15) of 16 bytes to camera body 11, outputs a data transmissioncompletion signal and permits communication interruption. The process isthen returned (S1091-S1094).

PZ OPERATION FOR BODY

An operation relating to power zooming at the camera body 11 side willbe explained below with reference to a flow chart shown in FIGS. 52 to55. This operation or processing is performed by the main CPU 35 on thebasis of a program stored in ROM 35a of the main (body) CPU 35 of thecamera body 11.

The process first enters the operation of the main flow, when main CPU35 is reset, such as when the main switch is turned on (when a batteryis inserted and electricity is generated). The process, when enteringthis operation, initializes RAM 35b, port setting, etc., inputspredetermined information by means of switch input or E² PROM DATAINPUT, and performs a power zoom initializing operation (PZINITsubroutine) (S1101, S1103, S1105). In this embodiment, power zoominitialization is an operation by which initialization of the PZ lensand focusing lens is conducted, for the purpose of detecting positionsof the zooming lens and focusing lens. The above steps are done uponinitial input of power (i.e., when a main switch which is not shown isturned on). While electricity is supplied, the following steps (fromS1107) will be repeated.

In S1107, predetermined information is inputted. If locked (i.e., when amain switch is turned on), photographing operation is possible, andhence the process proceeds with the necessary operations. If the lock isreleased (i.e., when the main switch is turned off), the processproceeds to a lock operation at and after S1181 (S1109).

When the lock is released for the first time, or if the process isperformed for the first time after the photographing lens is mounted,flag F₋₋ NEWCOM (a flag which is set up when new communication isperformed relative to the photographing lens after completion of oldcommunication) is cleared, and a PZ initializing flag F₋₋ PZINIT iscleared so as to perform initialization of power zooming (S1109-S1115,S4901, S1121, S1123).

In the case that the lock is not initially released or the process doesnot perform an operation for the first time after the photographing lensis mounted, but the status is a first AF mode or first PZ mode, flag F₋₋PZINIT is cleared in order to initialize various operations and datarelating to AF, PZ, the flag being set when such data are initializedetc. The process then calls a PZINIT subroutine (S1111, S1113, S1117,S4901, S1121, S1123).

The process inputs switch information and performs an operation (PZLOOPsubroutine) relating to power zooming and gives the necessary indicationon the display panel. The process then proceeds to S1133 (S1127-S1131).

Whether or not the photometering switch SWS (AF switch) is made ON ischecked, that is, whether or not the release switch is half-waydepressed is checked in step S1133. If the photometering switch SWS ismade OFF, control proceeds to step S4501 to check whether or not the AFmode is selected. In the illustrated embodiment, the AF mode, in whichautomatic focusing is effected, is set when the AF switch is made ON,and the MF mode, in which focusing is manually effected by the rotationof the focusing ring by the photographer, is set when the AF switch ismade OFF, respectively.

If the AF mode is not set and the MF mode is set in step S4501, controlproceeds to step S4503 to clear the ISZ memorization requesting flag F₋₋ISZMREQ to thereby store the focal length at ISZ. Thereafter, the AFoperation requesting flag F₋₋ PZAFREQ, requesting the AF operationduring the power zoom driving operation, is cleared in step S4505.Thereafter, control proceeds to step S1135 to turn off the power sourceVdd for the photometering. IC, the CCD, the E² PROM and a part of theperipheral control circuit. Then, control proceeds to step S1136 tocheck whether or not the flag F₋₋ AF is cleared. If the flag F₋₋ AF iscleared, control is returned to START. If the flag F₋₋ AF is set,control proceeds to step S1165.

If flag F₋₋ AF is set, it is likely that AF processing and constantimage magnification ratio zooming relating thereto have already beenperformed before photometric switch SWS is turned off. Accordingly, aconstant image magnification ratio zooming stop flag F₋₋ ISZSTOP is set,and an operation to stop constant image magnification ratio zooming andto check whether or not the same has been stopped (IPZENDCHECKsubroutine) is performed (S1136, S1165, S1167).

The process then clears focusing flag F₋₋ INFOCUS, performs an AF motorstopping operation, sends driving information of AF, etc. to powerzooming lens 51 by means of PZ-BSTATE command communication, clears flagF₋₋ AF, and proceeds to step S1176 (S1169, S1171, S1173, S1175).

If the AF mode is set in step S4501, control proceeds to step S4507where it is checked whether or not the ISZ memorization requesting flagF₋₋ ISZMREQ is cleared. Thereafter, if the AF operation requesting flagA₋₋ PZAFREQ is cleared in step S4509, neither the memorization at ISZnor the AF operation during the power zooming are requested. If thepower zoom source is made OFF in step S4511, control proceeds to stepS1135 to make OFF the power source Vdd for the photometering IC, theCCD, the E² PROM and a part of the peripheral control circuit.

If the power zoom source is made ON in step S4511, control proceeds tostep S4513 to carry out the PZ-LSTATE communication and receive the ONor OFF data of the manual power zoom from the side of the power zoomlens 51. Thereafter, in step S4515, whether or not the manual power zoomhas an ON/OFF state is checked in accordance with the result of thePZ-LSTATE communication obtained in step S4513. If the manual power zoomis made OFF, it is considered that the photometering switch SWS is madeOFF and the zoom operation ring is not rotated in the AF mode.Thereafter, control proceeds to step S1135 to make OFF the power sourceVdd for the photometering IC, the CCD, the E² PROM and a part of theperipheral control circuit.

If the manual power zoom is made ON in step S4515, it is considered thatthe photometering switch SWS is made OFF and the zoom operation ring isrotated to vary the focal length in the AF mode. Consequently, controlproceeds to step S4517 to set the AF operation requesting flag F₋₋PZAFREQ to request the AF operation. Thereafter, control proceeds tostep S1137 to make ON the power source Vdd (apply a constant voltage),and the photometering and calculation for the exposure are then carriedout and the results thereof are indicated in step S1138.

Namely, in the prior art, the AF operation is commenced only when thephotometering switch SWS is made ON, and an AF operation is not effectedas long as the photometering switch SWS is made OFF, even if the zoomoperation ring is rotated. Whereas, in the illustrated embodiment of thepresent invention, even if the photometering switch SWS is made OFF,when the zoom operation ring is rotated to vary the focal length, the AFoperation is commenced. Thus, the AF operation is effected when the zoomoperation ring is rotated to vary the focal length, regardless of theON/OFF state of the photometering switch SWS in the present invention.

As a matter of design of a zoom lens, it is preferable that the focusingposition at the tele photo extremity concurs with that at the wide-angleextremity so that a deviation of focus does not take place even when thefocal length is varied. It is, however, very difficult in practice tomake the focusing position at the telephoto extremity preciselycoincident with that at the wide-angle extremity. As a result, there isa small possibility that an object image is out of focus due to thechange of the focal length. To prevent this, as shown in the illustratedembodiment, the AF operation is effected when the zoom operation ring isrotated to vary the focal length, regardless of the state of thephotometering switch SWS, as mentioned above. Accordingly, aphotographer can observe an object image in focus through the viewfinder at any focal length.

With the prior art, when the photometering switch SWS is released uponcompletion of the photographing operation, the latest focal length andfocal point corresponding to the object distance are temporarilyretained. It is assumed for the purpose of the present invention that anew object at an object distance different from the object distance ofthe previous object, whose picture has just been taken, is observedthrough the view finder after the focal length is varied (i.e., afterthe power zooming is effected). In the prior art, once the photometeringswitch SWS is released, an AF operation is not effected, as mentionedabove. Accordingly, the previous object is maintained in focus, but thenew object to be observed through the view finder is out of focus, whichis rather inconvenient. With the illustrated embodiment of the presentinvention, when the zoom operation ring is rotated to effect the powerzooming operation, the AF operation is carried out, even if the releasebutton has been released so that the photometering switch SWS is alsomade OFF. Consequently, the photographer can perform the power zoomingoperation while observing the object image which remains continuously infocus.

If the photometering switch SWS is made ON in step S1133, the AFoperation requesting flag F-PZAFREQ is cleared in step S4519, andthereafter, control proceeds to step S1137. Namely, if the photometeringswitch SWS is made ON, the AF operation requesting flag F₋₋ PZAFREQ iscleared. This means that when the photometering switch SWS is made ON,the AF operation is commenced regardless of the rotation of the zoomoperation ring, and accordingly, the power zooming operation. In this AFoperation, a precise focusing operation is effected, as will bediscussed below. On the other hand, in the AF operation caused when theAF operation requesting flag F₋₋ PZAFREQ is set, the focusing range isenlarged, so that a relatively coarse focusing is carried out, as willbe discussed hereinafter. To this end, the precise AF operation to becarried out when the photometering switch SWS is made ON, after the AFoperation requesting flag F₋₋ PZAFREQ is cleared, is set prior to thecoarse AF operation to be carried out when the AF operation requestingflag F₋₋ PZAFREQ is set.

If the ISZ memory requesting flag F₋₋ ISZMREQ has already been set instep S4507 or the AF operation flag F₋₋ PZAFREQ has already been set instep S4509 when the photometering switch SWS is turned OFF and when theAF mode is set, control proceeds to step S1137.

The power source Vdd is made ON (a constant voltage is applied) in stepS1137, and then the detection and calculation necessary for the exposureare carried out and the results thereof are indicated in step S1138.Thereafter, in step S1139, whether or not the mode is the AF mode ischecked. If the AF mode is not selected, control skips to step S1165. Ifthe AF mode is selected in step S1139, the AF flag F₋₋ AF is set in stepS1140. Thereafter, the photometering operation, i.e., the integration,is commenced in step S1143. The integral data is then fetched to performthe prediction operation, and control proceeds to step S1145.

If the prediction operation result is appropriate in step S1145, and ifthe AF operation requesting flag F₋₋ PZAFREQ is cleared in step S4521,whether or not the image is focused is checked in step S1149. If theimage is in focus, a flag F₋₋ INFOCUS is set in step S4525. Thereafter,the focusing operation is carried out in step S1151. Thereafter, the AFoperation requesting flag F₋₋ PZAFREQ is cleared in step S4527, and theoperation for a moving object is carried out in step S1159.

If the object is out of focus in step S1149, whether or not the powerzoom lens is mounted is checked in step S1153. If a power zoom lens isnot mounted (F₋₋ PZ=0), control jumps to step S1176. Conversely, if thepower zoom lens is mounted, the AF drive data etc., is sent to the powerzoom lens 51 by the PZ-BSTATE command in step S1155. Thereafter, the AFmotor 39 is driven in step S1157, and control proceeds to step S1159.

If the prediction calculation results are appropriate at step S1145, andif the AF operation requesting flag F₋₋ PZAFREQ is set in step S4521,the operation to expand the focusing range is carried out in step S4523,prior to the checking operation in step 1149. Namely, in the operationin step S4523, the tolerance within which the image is determined to bein focus is increased. For example, the focusing range of the focusingoperation, which is carried out when the photometering switch SWS ismade ON, is doubled (in absolute value).

Namely, the AF operation, which is compulsively effected, when thephotometering switch SWS is made OFF and the zoom operation ring isrotated, is not directly for the focusing upon taking a picture, butmerely for the maintenance of the focused state when the focal length isvaried or when the photographer performs the framing operation whileobserving the object image through the view finder. Therefore, noprecise focusing is needed. On the other hand, the focusing operationupon taking a picture must be precisely effected so that the focusingrange is restricted to a small tolerance. Furthermore, it may arise thatno focus position may be found upon taking a picture. In such a case, afocus position is searched for by reciprocally moving the AF motorbetween the near position and the far position. However, the searchoperation is troublesome. In particular, if the search is effectedduring the zooming operation when a photographer does not intend to takea picture, the photographer might be disturbed.

Under these circumstances, in the preferred embodiment of the presentinvention, as mentioned above, when the flag F₋₋ PZAFREQ is set, sincethe focusing range is expanded at step S4523 prior to the checkoperation of the focus state at step S1149 and the control skips thesearch operation at step S1147, the focusing can be easily effected.Consequently, the photographer is not disturbed by the troublesomesearch operation.

If the prediction calculation results are not appropriate (not within aneffective range) at step S1145, namely, for example, if the contrast ofthe object is too low, the flag F₋₋ PZAFREQ is cleared at step S4529,and the searching is effected to obtain an effective value at stepS1147. Thereafter, the control proceeds to step S1153 to check whetheror not the power zoom lens is mounted. The searching operation refers toan operation to perform the integral while reciprocally moving the AFmotor 39 to obtain an effective defocus value. If the flag F₋₋ PZAFREQis set at step S4529, the control proceeds to step S4531 to clear theflag F₋₋ PZAFREQ without effecting the searching operation. Thereafter,the control Jumps to step S1176.

When the focusing operation at step S1151 is completed and the flag F₋₋PZAFREQ is cleared at step S4527 or when the AF motor 39 is driven atstep S1157, the control proceeds to step S1159 to carry out theoperation necessary for the moving object. Thereafter, at step S1161,whether or not the mode is the constant magnification zoom mode ischecked. If the constant magnification zoom mode is selected, theconstant magnification zoom operation is carried out at step S1163.Thereafter, the control proceeds to step S1176 to perform the checkoperation of the release switch SWS.

At step S1176, the process checks if release switch SWR has been turnedon. If the release switch is turned off, the process is immediatelyreturned to START. If the release switch is turned on, the process isreturned to START after performing a releasing operation, provided thatrelease is permitted (S1176, S1178, S1179).

If the lock is effected (i.e., the main switch is turned off) uponchecking at S1109, the process proceeds to S1181. If the lock iseffected for the first time in this routine and if in the power zoomingmode, the process proceeds to a retrieval operation (S1184-S1209) inorder to retrieve to the camera body the focal length data stored in thepreset zoom set mode. Otherwise, the process jumps to step S1223 (S1181,S1183).

If the lock is not effected for the first time, or if the photographinglens is not a power zoom lens, the process shuts off constant voltagesupply (CONT) and power supply (VBATT) to the photographing lens, andclears the indication on display 45. The process is then returned toSTART (S1181, S1183, S1223-S1227).

In the retrieval operation, the address of the memory (RAM 61b) to beretrieved is designated by means of a SET-PZPOINT command in order toretrieve the focal length stored in lens RAM 61b to the body. Then, thefocal length data stored in the address designated by the FOCALLEN-Xcommand is inputted from lens 51, so as to store them in body RAM 35b ataddress FLM as focal length data (S1184, S1185, S1187). IMAGE-LSIZE dataincluding image magnification ratio is inputted from lens RAM 65b so asto store the image magnification ratio data in the body RAM 35b ataddress ISM, and LENS-INF2 data is inputted from RAM 65b. The processthen proceeds to step S1195 (S1181-S1193).

In this embodiment, the image magnification ratio data is transferred tothe camera body in order to simplify the process of communication in theretracting operation. However, it is also possible for both the focallength data, which is obtained when an image magnification ratio is set,and the amount of lens movement data, regarding lens retraction, to betransferred.

At steps S1195 and S1197, the process checks whether accommodation ofthe power zoom is possible or power zoom is to be effected based on thedata input by a LENS-INF2 command. If it is impossible to accommodatethe power zoom or power zoom is not to be effected, the processimmediately proceeds to CONT1. If power zoom accommodation is possibleand power zoom is to be effected (flag F₋₋ RETPZ=1, F₋₋ PZD=1), the bodyside requests BBATreq to check the battery. When the battery is normal,a command (RETRACT-PZ) to cause the power zoom lens 51 to perform apower zoom accommodation operation is sent, a flag F₋₋ IPZON to identifythat controlled zooming is being performed is set, and a NG timer isstarted. The process then proceeds to a CONT1 operation (S1195-S1209).As mentioned above, since the preset zoom is included in the auto(control) zoom, as long as the preset mode is selected, the preset driveis indicated when the flag F₋₋ IPZON is set.

If the battery is found to be abnormal during battery checking, theprocess proceeds to the CONT1 operation (S1203). It should be noted thatflag F₋₋ RETPZ relates to information inherent to the lenses. This flagwill be cleared when the zooming lens is, for example, an inner zoominglens and hence the lens does not require accommodation or retractionthereof, so that an accommodation or retraction operation is notperformed.

In the CONT1 operation, it is checked, based on the AF retraction flagF₋₋ RETAF inputted by the LENS-INF2 command, whether the power zoom lens51 is AF-retractable or in an AF mode. If the lens is AF-retractable andin the AF mode, the focusing lens 53F is returned to a retractedposition by driving the AF motor 39 (S1211-S1215). Then, if controlledpower zooming is being effected, a standby is continued until powerzooming has ended, while checking the operation of the controlled powerzoom. When power zooming ends, the constant voltage supply and power tothe camera lens are turned off and the display 45 is also turned off,resulting in a return to the start (S1217-S1227). If the lens is notAF-retractable or not in the AF mode, the lens retraction operation isskipped. The flag F₋₋ RETAF is information inherent in the lens and iscleared when the zoom lens is an inner focusing type and a retraction ofthe focusing lens is not necessitated, as a result of which noprocessing for the retraction is performed.

PZINIT, AF-INIT OPERATION

Hereinafter, the initialization operation of the power zoom lens 51 tobe controlled on the body 11 side will be described with reference to aPZINIT subroutine as shown in FIGS. 56 to 58.

In the operation, the power zoom lens 51 initializes both the zoominglens group 53Z and the focusing lens group 53F and returns theinformation, protected against the turning off of the main switch in thebody, to the lens 51. In detail, the former is an operation whichdetects the positions of the zooming lens and the AF lens, while thelatter is an operation for again returning to the lens 51 (the lens RAM65b) an image size of ISZ and a focal length for a preset zoom, whichare held in the body RAM 35b when the main switch is turned off (orlocked).

If this processing is initiated for the first time, a new communicationflag F₋₋ NEWCOM indicative of the end of the old communication iscleared and thus the old communication is performed to communicate withthe lens ROM in synchronization with the clock of the camera body 11.After that, the old communication is switched to the new communicationwhich communicates with the lens CPU 61 in synchronization with theclock of the lens CPU 61 (S1301, S1303).

If an attached camera lens is not a Kz lens (including the power zoomlens 51 embodying the present invention) having the lens CPU, the newcommunication is impossible so that the flow is returned. On thecontrary, if the lens is the Kz lens, an input of data from the cameralens is effected by the new communication LENS-INF2 (14) and it ischecked if the attached lens is the power zoom lens (PZ lens) (S1305,S1309). If it is not the PZ lens, a flag F₋₋ PZ identifying the PZ lensis cleared and, the flow advances to step S1323 (S1309, S1311).

If the attached lens is the PZ lens, the flag F₋₋ PZ is set. When areset is effected in the camera body 11 (or when the battery isexchanged) or when the lens is first attached to the camera body 11, aninitial value is stored in an image size memory (ISM) (S1313, S1315,S1319). In the other cases, information regarding the focal length for apreset zooming operation and the like, sheltered in the body RAM 35b, isstored through a STORE-PZF (28) communication at a predetermined address(FCLOL, H to FCL7L, H) of the lens RAM 61b for the lens CPU 61. Then, aSTORE-IS (29) communication is performed so that the image size,sheltered in the RAM (35b) of the body CPU or the image size of theinitial value set at step S1319, is stored at predetermined addresses(ISZ-IMGL, H) of the RAM (61b) for the lens CPU, and a new communicationflag is set (S1321, S1323).

Next, the data is inputted through a POFF-STATE (11) communication fromthe lens CPU 61, and then the flow is sent to step S1361 where a standbyoperation is performed if the flag F₋₋ PZINIT, which indicates thatinitialization of the power zoom has been completed, is set or if theflag F₋₋ PZ has been cleared (S1325 to S1329).

If the flag PZINIT is cleared and the flag F₋₋ PZ is set, and when powerzooming is not performed (i.e., when a flag F₋₋ PZD (bit 5 of POFF-STATEdata) is cleared), that is, when manual zooming is performed, the flowadvances to an AF initialization (AFINIT) operation (S1325 to S1331).When the power zoom mode is used, a flag F₋₋ BBATREQ, requesting powersupply for PZ, is set and the power zoom lens 51 is supplied with powerby means of the BATONOFF subroutine. Further, it is checked whether ornot the power is supplied thereto in a normal manner (S1331 to S1337).If the power from the battery is not outputted to the power zoom lens 51in a normal manner thereto (i.e., flag F₋₋ BATNG=1), the flow advancesto the AFINIT operation. On the contrary, if the power supply is normal(the flag F₋₋ BATNG=0), a PZ-INITPOS command (32) is outputted to forcethe camera lens to initialize PZ. Further, the flow advances to theAFINIT operation after setting up the flag F₋₋ IPZON, indicating thatinitialization of PZ has been completed.

AFINIT OPERATION

A flowchart for an AFINIT operation, as shown in FIGS. 57 and 58, is anoperation for initialization of the AF. Further, in the present case,the AF is initialized after initialization of PZ. However, the AF may beinitialized before initialization of PZ.

In the AFINIT operation, under the condition that the camera lens is inthe AF mode, a focusing lens 53F is moved to the retracted position, atwhich point the tube length is minimized (S1341, S1343). Specifically,the position is the far (i.e., infinity) position. The initializationdata is then inputted by an AFINITPOS communication and a flag F₋₋AFINIT is set (S1345, S1347). Also, upon initialization, the lens CPU 61generally initializes the lens RAM 61b for AF-pulse counting.

Next, if a flag F₋₋ IPZON, indicative of power zooming other than manualpower zooming being effected, is set, it is checked in an IPZENDCHECKsubroutine whether or not the initialization of power zooming is ended(S1349 to S1353). When the initialization of power zooming has ended, aflag F₋₋ PZINIT, identifying the end of power zooming initialization, isset while a battery request flag F₋₋ BBATREQ at the body side is set to"0". Further, in a BATONOFF subroutine, it is requested to stop thepower supply and it is checked if the stop has been completed (S1355 toS1359).

Then, if the power supply for the photometric IC 17, CCD 21 and E² PROM43 and the like of the body 11 are turned on (Vdd ON), the flow isreturned. However, if they are turned off, a STANDBY command iseffected, and the flow is returned after the lens CPU 61 of the cameralens 51 is set in a standby state (a transfer to a low power consumptionmode) (S1361, S1363).

BATONOFF OPERATION

A BATONOFF flowchart, as shown in FIG. 59, illustrates a checkingoperation performed by main CPU 35, wherein it is checked whether powerfor the zoom motor 65 is normally supplied from the camera body 11 tothe power zoom lens 51 upon issuance of a power request (or a batteryrequest) from the body or the lens. In the present case, such a batteryrequest may be issued by either of camera body 11 itself or the cameralens 51.

In the BATONOFF operation, first of all, if the battery request is notissued from either of the power zoom lens 51 or the camera body 11, theflow is returned when power supply to the VBATT terminal has beenalready stopped (i.e., when flag F₋₋ BATON has been cleared (S1401,S1403, S1405)). However, when the power supply is effected the powersupply to the power zoom lens 51 is turned off, the flag F₋₋ BATON iscleared, a BODY-STATE0 output command is issued so as to sendinformation indicative of the power supply being turned off (BATT of bit5 is cleared) to the lens. Thereafter the flow is returned (S1421 toS1425).

When the battery request is issued from the power zoom lens 51 or thecamera body 11 (i.e., when a LBATREQ or BBATREQ of bit 1 of thePOFF-STATE data is set) and if the power is not yet being supplied, thepower zoom lens 51 starts to be supplied with power and BODY-STATE0data, concerning the body state, transmits information indicative of thepower supply being supplied (i.e., a BBAT of bit 5 is set) to the lens.After the flag F₋₋ BATON, identifying power supply under way, is set,POFF-STATE data is inputted. However, if the power supply is alreadyturned on, the flow goes directly to step S1415 where POFF-STATE data isinputted (S1407 to S1415).

If the battery supply is normal (i.e., flag F₋₋ BDET=1 in bit 0 ofPOFF-STATE), the flow is returned (S1417). However, if the batterysupply is abnormal, for example, in the case of a short circuit, a flagF₋₋ BATNG identifying the battery abnormality is set, power supply tothe power zoom lens 51 is cutoff, and flag F₋₋ BATON is cleared.Further, a BODY-STATE0 command is issued to send to the lens informationregarding the "ON" state of the power supply and then the flow isreturned (S1419 to S1425). The flag F₋₋ BATNG is cleared at step S4903when the flag F₋₋ BDET is set at step S1417.

PZ-LOOP OPERATION

The PZ-LOOP operation shown in FIGS. 60A, 60B and 61A is the powerzooming operation performed by the main CPU 35. In the PZ-LOOPoperation, the preset zoom (clipping - PSZ) operation to effect powerzooming to obtain the preset focal length, the focal length settingoperation (PSZS), and the constant magnification zoom operation (ISZ),etc., are carried out in connection with the power zoom operation.

In the illustrated embodiment, as will be discussed hereinafter, whenthe zoom set button 77 (i. e., the PZ mode switch SL) is pressed down inthe preset zoom mode (PSZ), the AF operation is commenced regardless ofthe ON/OFF state of the photometering switch SWS to effect the powerzooming operation until the preset focal length is obtained.Consequently, the photographer can observe the focused object image,during power zooming to the preset focal length, through the viewfinder.

When the zoom set button 77 is pressed down in the preset zoom set mode(PSZS), the current focal length which can be optionally set by rotatingthe zoom operation ring 78 is stored. When the preset zoom set mode isset, no AF operation is carried out when the zoom set button 77 ispressed down, but the AF operation is carried out by the rotation of thezoom operation ring 78 when the photometering switch SWS is made OFF, asdiscussed above with reference to FIG. 53A. Consequently, thephotographer can perform the framing, while observing the object imagein focus through the view finder, when the focal length is varied in thepreset zoom set mode.

When the zoom set button 77 is pressed down at the constantmagnification zoom (ISZ) mode, the AF operation is carried out bysetting the ISZ memory requesting flag F₋₋ ISZMREQ, and the imagemagnification at that time determined in accordance with the objectdistance and the focal length of the focused object is stored.

When the control enters the routine of the PZ-LOOP operation, whether ornot the flag F₋₋ NEWCOM is set is checked at step S1501. If the flag F₋₋NEWCOM is cleared, namely, if the new communication is not available,the control is returned without performing any operation. Conversely, ifthe flag F₋₋ NEWCOM is set at step S1501, and if the flag F₋₋ PZ is setat step S1503, namely, if the new communication and the power zoomingare available, the control proceeds to step S1505 to effect thenecessary operations which will be discussed below.

If the flag F₋₋ PZ is cleared at step S1503, and if the newcommunication is available and no power zooming is permitted, thecontrol proceeds to step S1504-1 to perform the BODY-STATEOcommunication. In the BODY-STATEO communication, the data, such as modedata of the power zoom, on the camera body side is sent to the lens. Ifthe power source Vdd is made ON at step S1504-2, the control proceeds tostep S1504-3 to input the lens data, such as switch data on the lensside through the POFF-STATE communication. If the power source Vdd ismade OFF at step S1504-2, the control proceeds to step S1504-4 to inputthe lens data through the POFF-WSLEEP communication. Consequently, thelens CPU 61 is transferred to the stand-by mode (i.e., low powerconsumption mode). The lens CPU 61 maintains the low power consumptionmode in accordance with the POFF-WSLEEP command until the lens CPU 61receives a subsequent communication command. After the operation at stepS1504-3 or S1504-4 is completed, the control is returned.

At step S1505, the data, such as the switch data of the power zoom lens51 is input through the POFF-STATE communication. Thereafter, the PZmode is switched in accordance with the input data and the altered modeis indicated at step S1507. Thereafter, the power is supplied or thepower supply is stopped at step S1509. Thereafter, the BODY-STATEOcommunication is carried out at step S4601. In the BODY-STATEOcommunication, data, such as the power zoom mode data on the camera bodyside is sent to the lens. If the power source Vdd is made ON at stepS4603, the control proceeds to step S4605 to input the lens data, suchas switch data on the lens side through the POFF-STATE communication. Ifthe power source Vdd is made OFF, the control proceeds to step S4607 toinput the lens data through the POFF-WSLEEP communication. Consequently,the lens CPU 61 is transferred to the stand-by mode. The lens CPU 61 ismaintained in the stand-by mode in accordance with the POFF-WSLEEPcommand until the lens CPU receives a subsequent communication command.After the operation at step S4605 or S4607 is completed, the controlproceeds to step S1513.

At step S1513, whether or not the preset zoom (PSZ) mode (i.e., clipmode) is selected is checked. If the mode is the PSZ mode, the ISZmemory requesting flag F₋₋ ISZMREQ is cleared to stop the memorizationas a part of the initialization at step S4701. Thereafter, the flag F₋₋ISZSTOP is set at step S1515 to forbid the constant magnification zoomoperation. Thereafter, the IPZENDCHECK sub-routine is performed at stepS1517, ending the constant image magnification zooming. After that,whether or not the zoom set button 77, attached to the side portion ofthe power zoom lens 51, is actuated is checked. In other words, whetheror not the preset zoom drive is commenced is checked at step S1519. Tothis end, the edge of the rising portion of a pulse that switches fromthe ON state to the OFF state is detected, i.e., the moment at which thezoom set button 77 is pressed down is detected.

If preset zoom drive is not commenced (i.e., if zoom set button 77 isnot pressed down), whether or not the flag F₋₋ IPZON is set is checkedat step S4703. If the flag F₋₋ IPZON is cleared, that is, if no presetzoom drive is commenced, the control is returned. Consequently, if theimage is focused at step S1149 (FIG. 53B), the flag F₋₋ PZAFREQ iscleared to stop the AF operation at step S4527. Accordingly, if theimage is focused when the preset zoom (clip) operation is completed, noAF operation continues.

If the flag F₋₋ IPZON is set at step S4703, i.e., the zoom set button 77has been pressed down and the preset zooming is being effected, thecontrol proceeds to step S4705 to set the flag F₋₋ PZAFREQ to continuewith the AF operation. Thereafter, the control is returned. This isbecause, if the control was directly returned, the AF operation would bestopped immediately when the image is once focused. Namely, even if theimage is out of focus during the preset zoom (clip) operation, the AFoperation continues to try to obtain a focused object image as long asthe preset zoom operation continues.

If the preset zoom drive is commenced at step S1519, the flag F₋₋PZAFREQ is set at step S4707 to drive the AF operation. Namely, in theillustrated embodiment, the AF operation is commenced immediately afterthe zoom set button 77 is pressed down, independently of thecommencement of the preset zoom operation. As a result, the AF operationis commenced when the zoom set button 77 is actuated to start the presetzoom operation so that the image is always kept in focus during thepreset zoom operation.

After the AF operation is commenced, whether or not the preset zooming(clipping) is being carried out (F₋₋ IPZON=1) is checked at step S1521.If the preset zooming is being carried out, whether or not the presetzooming operation is completed, in the IPZEND check sub-routine, ischecked at step S1555. Thereafter, the control is returned.

If the preset zoom operation is not commenced at step S1521, the camerabody 11 demands power supply thereto at step S1523. Consequently, poweris supplied at step S1525. Thereafter, whether or not the battery isnormal is checked at step S1527. If the battery is defective, thecontrol is returned. Conversely, if the battery is normal, the controlproceeds to step S1529 to transmit the MOVE-PZMD command to effect thepower zooming so that the zoom lens is moved to the focal lengthposition stored at a designated address. Thereafter, the flag F₋₋ IPZONis set at step S1531 to indicate that the preset zooming is beingeffected.

If no preset zoom (PSZ) mode is set at step S1513, the control proceedsto step S1541 to check whether or not the preset zoom set (PSZS) mode(i.e., the clip set mode) is set. If the preset zoom set mode is set,the control proceeds to step S4709 to clear the ISZ memory requestingflag F₋₋ ISZMREQ. Thereafter, the flags F₋₋ ISZSTOP and F₋₋ IPZSTOP areset to stop the constant magnification control and the auto zoom drive(preset zoom drive) at step S1543. Thereafter, the preset zoom drive orthe constant magnification zoom drive is stopped in the IPZENDCHECKsub-routine at step S1545.

Whether or not the zoom set button 77 is pressed down and the presetzoom set mode is indicated are checked at step S1547, similar to stepS1519. If the zoom set button 77 is actuated, the control proceeds tostep S1549 to send the STORE-PZP command to the power zoom lens 51 tostore the current focal length data in the lens CPU 61 at a designatedaddress of the lens RAM 61b. Thereafter, the preset zoom set (PSZS) modeis changed to the preset zoom (PSZ) mode at step S1551. Namely, once thecurrent focal length data is stored, the mode is automatically switchedto the preset zoom (clip) mode. Thereafter, the values of bits 0-2 ofthe BODY-STATEO command are modified, and then, the BODY-STATEO commandis output to give information on the change into the preset zoom mode tothe power zoom lens 51. Thereafter, the control is returned. If the zoomset button 77 is not actuated at step S1547, no operation is carried outand the control is returned. Namely, preset zoom mode (clip set mode) ismaintained.

If no preset zoom set (PSZS) mode is set at step S1541, namely, ifneither the preset zoom mode (clip mode) nor the preset zoom set mode(clip set mode) are set, the control proceeds to step S1561 to checkwhether or not the constant magnification zoom mode (ISZ) is set. If theconstant magnification zoom mode (ISZ) is set, the flag F₋₋ IPZSTOP isset to stop the preset zoom at step S1563. Thereafter, the IPZENDCHECKsub-routine is carried out at step S1565. Thus, the preset zooming iscompleted.

Thereafter, the LENS-INF1 data is input at step S1569, and whether thepower zoom switch PZSW is made ON by the rotation of the zoom operationring 78 to modify the focal length is checked at step S1571. If thepower zoom switch PZSW is made ON, namely, if the focal length is beingmodified, the control proceeds to step S4711 to clear the ISZ memoryrequesting flag F₋₋ ISZMREQ, since no focal length can be stored duringthe modification. Thereafter, the flag F₋₋ PZWAIT is set to forbid theconstant magnification zoom ISZ, and the control is thereafter returned.

If the power zoom switch is made OFF at step S1571, namely, if the zoomoperation ring 78 is not rotated (i.e., the zooming operation iscompleted or is not effected), the control proceeds to step S4715 tocheck whether or not the zoom set button 77 is pressed down, similar tostep S1519. If the zoom set button 77 is pressed down, the controlproceeds to step S4717 to set the ISZ memory requesting flag F₋₋ISZMREQ. Thereafter, whether or not the image is in focus is checked atstep S4719. If the image is focused, the control proceeds to step S4721to output the ISZ-MEMORY command to the taking lens to store the imagemagnification. Thereafter, the ISZ memory requesting flag F₋₋ ISZMREQ iscleared at step S4723, and the flag F₋₋ PZWAIT, which forbids thecommencement of the constant magnification zoom ISZ, is cleared at stepS4725, so that the constant magnification zoom operation ISZ ispermitted.

If no image is focused at step S4719, the control proceeds to step S4713to set the flag F₋₋ PZWAIT to prohibit the constant magnification zoomISZ. Thereafter, the control is returned.

If neither the zoom set button 77 is actuated nor the zoom operationring 78 is rotated at step S4715, the control proceeds to step S4727 tocheck whether or not the ISZ memory requesting flag F₋₋ ISZMREQ is set.If the flag F₋₋ ISZMREQ is set, that is, if the zoom set button 77 hasbeen pressed down and the flag F₋₋ ISZMREQ has been set at step S4717,the control proceeds to step S4719 to check whether or not the image isfocused.

If the flag F₋₋ ISZMREQ is judged to be cleared at step S4727, the ISZmemory requesting flag F₋₋ ISZMREQ has been cleared at step S4723 afterthe judgement of the focus state of the object image. Accordingly, thecontrol proceeds to step S4725 to clear the flag F₋₋ PZWAIT to permitthe commencement of the constant magnification zooming so that theconstant magnification zooming can be carried out.

If at step S1561 it is judged that the mode is not the preset zoom(clip) mode, the preset zoom set (clip set) mode or the constantmagnification zoom mode, the ISZ memory requesting flag F₋₋ ISZMREQ iscleared at step S4729. Thereafter, flag F₋₋ IPZSTOP and flag F₋₋ ISZSTOPare both set at step S1585 to stop the preset zooming and the constantmagnification zooming. Thereafter, the IPZENDCHECK sub-routine iscarried out and the completion of the preset zooming is checked.

In the illustrated embodiment, the image magnification is stored inaccordance with the distance of the in-focus object and the focal lengthcorresponding thereto at the constant magnification zoom (ISZ) mode,when the zoom set button 77 is pressed down, as mentioned above. Thepresent invention is, however, not limited thereto. FIG. 61B shows amodified embodiment of FIG. 61A by way of example. In FIG. 61B, stepS4715 in FIG. 61A is replaced with step S4801. In FIG. 61B, stepscorresponding to those in FIG. 61A are designated with the samereference numbers and no detailed explanation of each step will begiven.

At step S4801, the OFF edge (i.e., the edge of a pulse portion switchingfrom ON to OFF) of the power zoom switch is detected to start thememorization of the image magnification. In other words, the objectdistance of the focused object and the corresponding focal length aremeasured to obtain and store the image magnification only when the OFFedge of the power zoom switch is detected. In the illustratedembodiment, the power zoom switch is switched from ON to OFF inaccordance with the return movement of the zoom operation ring 78 to aneutral position thereof. Consequently, when a photographer rotates thezoom operation ring 78 to set a desired focal length (with the AFoperation starting when the zoom operation ring 78 is first rotated), ifthe photographer releases the zoom operation ring 78 with the zoomoperation ring 78 automatically returning to the neutral position by areturn spring (not shown) incorporated in the camera, the power zoomswitch is switched from ON to OFF. Accordingly, the OFF edge of thepower zoom switch is detected. Thus, the operations subsequent to stepS4717 are carried out when the power zoom switch is made OFF. Namely,the object distance and the corresponding focal length are measured toobtain the corresponding image magnification which is then stored in thememory.

As can be understood from the foregoing, with the present invention, itis possible to store the image magnification in the constantmagnification zoom (ISZ) mode, in accordance with either the operationin which the photographer presses the zoom set button 77 or releases thezoom operation ring 78 after a desired focal length is set.

IPZENDCHECK OPERATION

An IPZENDCHECK flowchart, as shown in FIG. 62, is a body-side operationwhich finishes preset power zooming and constant image size zooming andchecks for the completion thereof.

Upon initiation of the IPZENDCHECK subroutine, during constant imagesize zooming completion and constant image size zooming-on (F₋₋ISZSTOP=1, F₋₋ ISZON=1) or during preset zooming completion and thepreset zooming-on (F₋₋ IPZSTOP=1, F₋₋ IPZON=1) state, an NGTIMER flagand an IPZEND flag are cleared, a transmission of an IPZ-STOP command tostop the power zoom is performed to clear the respective flags F₋₋ISZON, F₋₋ IPZON and BBATREQ, and the flow is returned after stoppingthe battery supply and checking it (S1601 to S1607, S1621-1 to S1631).

If the camera is not currently in the state of constant image sizezooming-on or preset zooming-on, a PZ-LSTATE data is inputted and it ischecked whether the power zoom lens 51 is in the preset zooming-on orconstant image size zooming-on states. If the camera is not currently inthe state of zooming-on (IPZB=0), a flag signifying a preset zoomingcompletion or constant image size zooming completion is set and the flowis returned (S1601 to S1617). If currently in the preset zooming-on orconstant image size zooming-on (IPZB=1) states, the flow is returnedunless an abnormal detection timer (NG timer) expires (S1619).

Since it is expected that an abnormal event has occurred if the NG(abnormality detection) timer expires before the end of constant imagesize zooming, a TIMEUP flag is set (F₋₋ TIMEUP=1) and a NGTIMER flag andIPZEND flag are cleared (F₋₋ NGTIMER=0, F₋₋ IPZEND=0) (S1621-1,S1621-2). Then, a power zooming stop operation is performed (S1623 toS1631). If the NG timer has not yet expired, the flow is directlyreturned.

ISZ-DRIVE1 OPERATION

A flowchart (ISZ-DRIVE1) as shown in FIGS. 63 to 66 is an operation inthe body CPU 31 in which the power zoom lens 51 (lens CPU 61) is forcedto perform a constant image size zooming operation. The ISZ-DRIVEoperation is called at S1163, as shown in FIG. 53.

When the focusing lens is at its infinite position, data concerning anAF position is transmitted to the power zoom lens 51 by an AF-INITPOScommand (S1701, 1703). When the focusing lens is at its near position,PZ body state data concerning the power zoom mode of the camera body istransmitted to the power zoom lens 51 by a PZ-BSTATE command (S1701,S1705, S1707).

If a power zoom wait (F₋₋ PZWAIT=1) has been effected or if the resultof a predictor operation is invalid, the flow is returned without anyprocessing (S1709, S1711). If power zoom wait has not been effected andthe result of the predictor operation is valid, the focus condition ischecked (S1709 to S1713). If in focus, it is checked if the NG timer hasbeen actuated (F₋₋ NGTIMER=1). If it has not been actuated, the NG timeris started and the flag F₋₋ NGTIMER is set, thereafter advancing to stepS1721 (S1713, S1715, S1719, S1720). If the NG timer has already beenactuated, the foregoing operation is skipped and the flow is advanced toS1721.

Next, after checking the completion of constant image size zooming atstep S1721 (IPZEND-CHECK), it is checked if the completion of the samehas occurred while in the constant image size zooming-on state (S1723,S1725). If in the constant image size zooming-on state (F₋₋ ISZON=1) andthe constant image size zooming has ended (F₋₋ IPZEND=1), the flag F₋₋IPZEND is cleared and the flag F₋₋ ISZSTOP is set. Further, the flow isreturned after an end operation of constant image size zooming isperformed in the IPZENDCHECK subroutine (S1725 to S1729).

If the camera is not in the constant image size constant zooming-onstate or if constant image size zooming has not ended, a transmission ofdata concerning the power zoom state in the camera body 11 is performedby a PZ-BSTATE command (S1723, S1725, S1731). Then, if the camera is notin the constant image size zooming-on state, power supply is requestedon the body side and a check of the battery supply is performed.Further, after a flag identifying the continuation of constant imagesize zooming is set, the flow advances to an in-focus judgment. However,if the camera is already in the constant image size zooming-on state(S1733 to S1741), the flow directly advances to the in-focus judgment.

If in focus, in order to perform constant image size zooming based onthe current AF pulse (i.e., the value of AFPXL, AFPXH), predetermineddata is transmitted to the power zoom lens 51 by the BODY-STATE 1command. Furthermore, after a transmission of a constant image sizezooming start (ISZ-START) command is effected to start constant imagesize zooming by the power zoom lens 51, the flow is returned (S1741 toS1745). If the camera is out of focus, defocus pulse data, measured bythe camera body 11, is transmitted by a STORE-DEFF & D command. Afterthat, data, by which the constant image size zooming is effected basedon the defocus pulse, is transmitted by a BODY-STATE1 command. Finally,a constant image size start command (ISZ-START) is transmitted, and theflow is returned.

ISZ-DRIVE2

Hereinafter, another alternative constant image size zooming operationas shown in FIGS. 65 and 66 will be described. This is characterized inthat the operations and controls concerning constant image size zoomingare performed in the camera body 11.

Since the operations from S1801 to S1823 are similar to those from S1701to S1731, explanations are omitted. Hereinafter the operations fromS1825 will be described.

If the lens is not focused, transmission of data concerning the powerzoom state of the camera body 11 is performed by a PZ-BSTATE command(S1813, S1825 to S1833). Then, if the power zoom lens 51 is notundergoing constant image size zooming, power supply is requested by thebody side. The battery supply operation and the checking thereof arethen performed. Additionally, a control zooming-on flag F₋₋ IPZON is set(S1827 to S1833).

Next, transmission of a SET-PZPOINT command is issued designating anaddress of the lens RAM 61b in which the focal length, at the time ofimage size storing, is stored, and an input of the focal length(FOCALLEN-X data), at the time of image size storing and designated bythe SET-PZPOINT command, is issued from the power zoom lens 51 (S1835,S1837). Further, a transmission of a SET-AFPOINT command is effectedwith a designation of the focal length data, at the image size storing,stored in the lens RAM 61b, and an input of the number of AF pulses(LENS-AFPULSE data), at the time of the image size storing, is effectedfrom the lens 51 (S1839,S1841). Then, the image size (x0f0) iscalculated based on the inputted data (S1843). Further, a transmissionof the SET-AFPOINT command is effected with a designation of the currentnumber of the AF pulses and an input of the current number of the AFpulses, (LENS-AFPULSE data) is effected based on the designation fromthe lens 51 (S1845, S1847).

Next, it is checked whether the lens is in focus and, in the case thatit is in-focus, the focal length is found from equation 4) by utilizingthe current number x of AF pulses. If not in focus, it is checked if thephotographing image is a moving object. If it is a moving object, thefocal length is calculated in the same manner as that of the in-focuscalculation, based on the present AF pulse. If it is not a movingobject, a target focal length is found from equation 5) utilizing thecurrent number x of AF pulses and defocus pulses Δx (S1849 to S1853).Then, after transmission of a command by which the power zoom isperformed to the operated target focal length and the focal length data(MOVE-PZF command), the flow is returned (S1855).

The lens CPU 61, receiving this MOVE-PZF command, drives the zoominglens 53F to the target focal length sent from the camera body.

In this case, the method for calculating the target focal length ischanged according to the focusing state of the photographing lens.However, the method may be changed according to other conditions, forinstance, the condition of whether or not the moving object predictionmode is being effected.

In this case, a judgement operation "Is the photographing image a movingobject?" is to be added before S1853. In the case of a moving object,the target focal length is calculated by the present lens moving amountat S1851. If not a moving object, the focal length is calculated atS1853. The reason why the target focal length is calculated withoututilizing defocus amount when the moving object prediction mode iseffective, is to make the driving speed of the lens faster and morestable.

ISZ-DRIVE3

A constant image size zooming operation, as shown in FIGS. 67 and 68,illustrates a further alternative. In this case, a modification ofconstant image size zooming is controlled at the body 11 side. Indetail, in the case that constant image size zooming is effected afterthe lens comes into focus once, the in-focus state may be shifted whenthe zooming is ended. Therefore, the AF operation and constant imagesize zooming are again effected after constant image size zooming hasended. In addition, this alternative is provided with a method fordriving the lens during constant image size zooming by changing itsspeed depending on the speed of the moving object at the time of themoving object prediction AF.

If the focusing lens 53F is in the far position, a AF-INITPOS command istransmitted to the taking lens (power zoom lens 51 (S1901, S1903). Ifthe focusing lens is in the near position, PZ body state data concerningthe power zoom mode of the camera body is transmitted to the power zoomlens 51 by a PZ-BSTATE command (S1901, S1905, S1907).

If the lens is in a power zoom wait mode or if the result of thepredictor operation is invalid, the flow returns without any processing(S1909, S1911).

If the lens is not in the power zoom wait mode and if the result of thepredictor operation is valid, it is checked whether a subject is amoving object (S1909 to S1913). If the subject is a moving object andthe constant image size zooming-on flag has been cleared (i.e., notduring constant image size zooming), the body battery request flag (F₋₋BBATREQ=1) is set and battery supply is effected. Further, the constantimage size zooming-on flag (F₋₋ ISZON=1) is set (S1961 to S1967). Then,the power zoom speed is set, depending on the speed of the moving object(moving speed on an image surface). A flag F₋₋ ISZD is cleared to effectthe ISZ control by using the set power zoom speed data and the AF pulseat the current position. Further, a transmission of an ISZ-START commandis effected through the BODY-STATE1 data communication to force thecamera lens 51 to commence constant image size zooming (S1969 to S1973).Note that when the flag F₋₋ ISZD to control the constant magnificationzoom (ISZ) is set and cleared, the focal length is controlled to be atarget value which is obtained using the defocus pulses and a targetvalue which is obtained using the current values of the AF pulses,respectively.

In the case that the object is not moving, it is checked if the lens isin-focus for the second time (F₋₋ INFOCUS=2) or the first time (F₋₋INFOCUS=1 (S1913, S1915, S1917)). Here, the F₋₋ INFOCUS is two bits. Ifthe lens is not in-focus for the first or second time, i.e., in aninitial state, it is checked if it is in focus. If not in-focus, theflow is returned. In the case of an in-focus condition, the body batteryrequest flag F₋₋ BBATREQ is set to effect the power supply, and theconstant image size zooming-on flag F₋₋ ISZON is set (S1919 to S1925).

Then, transmission of the constant image size zooming start command iseffected so that constant image size zooming and the NG timer arestarted. It is then checked if constant image size zooming has ended.When it has ended, the first operation is ended after a first in-focuscondition flag is set and a constant image size zooming end flag F₋₋IPZEND is cleared (S1935 to S1940).

The next time this operation is initiated, the flow moves from S1917 toS1941 because the first in-focus flag is set. It is then checked whetherit is again in focus. If not in focus, the flow is returned and theforegoing operation is repeated until an in-focus condition is achieved.If it is in focus, the NG timer is started and the constant image sizezooming start command is transmitted to the camera lens to force thecamera lens to start constant image size zooming. The flow is thenreturned after the second in-focus flag is set (S1943 to S1947).

If this ISZ-DRIVE 3 operation is initiated after the end of the S1947operation, the second in-focus flag is set so that the flow advancesfrom S1915 to S1951 and it is checked if constant image size (control)zooming has ended. If the control zoom has not ended, the flow isreturned. If the control zoom has ended, a control zoom end flag F₋₋IPZEND is cleared and constant image size zooming stop flag F₋₋ ISZSTOPis set. The flow is then returned after the constant image size zoomingend operation is performed (S1953 to S1957).

AFP-CNT OPERATION

An AFP-CNT operation, as shown in FIG. 69, is an AF pulse countoperation in the power zoom lens 51. The lens CPU 61 comprises an AFpulse counter for counting AF pulses outputted from the AF pulser 59 ina hardware manner. This AFP-CNT operation is initiated at 2 ms intervalsby a 2 ms timer interrupt. This operation illustrates, in detail, theoperation at S303 in the 2 ms timer interrupt routine, as shown in FIG.9.

In the AFP-CNT operation, a count value of the AF pulse hard counter isfirst stored in an AF pulse count value memory (addresses AFPCNTL, H ofthe lens RAM 61b (S2001)). Then, by reference to data (i.e., datainstalled in bit 3-0 of PZ-BDST, which is a predetermined address of RAM61b) concerning an AF operation which is inputted by PZ-BSTATE commandwhen the AF motor 39 is moving the lens to the near end and before itarrives at the near end, the AF pulse count value is added to the AFpulse count start value (AFPSTRTL, H) and this is stored in the currentAF pulse value memory (AFPXL, H of the lens RAM 61b) before ending theroutine. However, if it arrives at the near end, the flow immediatelyends (S2002 to S2007).

When the AF motor 39 is moving the lens to the far end and before itarrives at the far end, the AF pulse count value is subtracted from thecurrent AF pulse count start value and the result is stored in thecurrent AF pulse value memory (AFPXL, H) to end the AFP-CNT operation.If it arrives at the far end, the AFP-CNT operation is immediately ended(S2009 to S2013). Also, if the lens is neither moving towards the nearend nor the far end, the AF motor does not rotate. Therefore the AFP-CNToperation ends without any processing (S2002, S2009).

AFP-ADJ OPERATION

An AFP-ADJ flowchart as shown in FIG. 70 is an operation on the cameralens 51 side. It amends the current AF pulse value affected by backlashand the like. In the present case, the AF pulse value at the far end isset at zero and the AF pulse value at the near end is set at the maximumvalue. Then, the present AF pulse count is amended every time the brush85 crosses one of the indicators 83 on the distance code 81, inaccordance with an absolute pulse number, which is to be determined bythe position of the indicator 83, based on an absolute value code. Thepresent operation is a detail of the 2 ms timer interrupt routine atS307, as shown in FIG. 9.

Upon initiation of the AFP-ADJ operation, it is first checked if thebrush 85 has contacted the indicator 83. If not, the operation is ended(S2021). If contacted the brush, the flow is directly returned in thecase that such a contact was achieved during the preceding operation(S2021, S2023). In other words, at the time when the indicator 83 andthe brush 85 contact is detected (at an edge of the indicator 83).

If the indicator 83 and the brush 85 contact each other and such contactoccurs when the AF motor 39 is moving the lens to the far position, anAF pulse FAR table data (data concerning an edge at the near end side ofthe indicator 83) corresponding to the near end position of theindicator 83 is read and stored in addresses AFPCDL, H. If such contactoccurs during the near end movement, an AF pulse NEAR table data (dataconcerning an edge at the FAR end side of the indicator 83)corresponding to the far end position of the indicator 83 is read andstored in addresses AFPCDL, H (S2025 to S2033). The reason why there aretwo kinds of tables, i.e. the FAR table and the NEAR table is becausethe indicator 83 has a width and an absolute position at the contacttime which is different along the width, depending on the contactdirection. When the AF motor 39 is stopped, the flow is immediatelyended (S2027, S2031). Further, a flag F₋₋ AFPADJ at S2025 is providedfor test purposes and is usually cleared.

Next, if the current AF pulse value is known (when flag F₋₋ AFPOS isset), the current AF pulse count value (data of the AFPXL, H) issubtracted from the table data (AFPCDL, H) and its subtracted value(difference) is stored in an AF pulse error memory (AFPDIFXL, H (S2035,S2037)). Here, when the error is negative, the absolute value of theerror is stored in the AF pulse current value memory (S2039, S2041).

It is then checked if the difference is larger than an allowable error(N₋₋ AFPDIF). If the difference is smaller, the operation is directlyended. However, if the difference is larger, an amendment is effected,that is, the table data (AFPCDL, H) are incorporated into the current AFpulse value memory (AFPXL, H) and the AF pulse count start value memory(AFPSTARTL, H (S2043, S2045)). On the other hand, if the AF pulsecurrent value is not known, the amendment operation at S2045 isunconditionally performed (S2035, S2045).

Then, the AF pulse hard counter is cleared and started and the AF pulsecount start value (AFPCNTL, H) is cleared. After that, the flag F₋₋AFPOS, showing the current AF pulse value being known, is set and theoperation ends (S2047, S2049).

LMT-DTC OPERATION

A LMT-DTC flowchart as shown in FIG. 71 is an operation on the side ofthe camera lens 51. This operation detects that a zooming lens group 53Zhas arrived at an end point or that movement is prevented by someexternal circumstances (i.e., the lens group 53Z has arrived at apara-end point). Such detections are performed by checking if, duringthe drive of the PZ motor 65, the PZ pulses are outputted within apredetermined period of time. Further, the predetermined period of timeis changed depending on a driving speed of the PZ motor (zooming speed).Also, since a starting torque becomes larger for a constant period afterthe start of the PZ motor (i.e., upon a transfer from a stop state or abraking state to a driving state), the detection of the end point is notperformed. The present operation illustrates the detail of the 2 mstimer interrupt routine at S351, as shown in FIG. 10.

First, it is checked if the PZ motor is performing a driving operation.In the case of non-driving, the flow exits after clearance of a limitcounter T₋₋ LMT, which detects arrival at a limit (i.e., the end pointor the para-end point (S2061, S2071)). Specifically, a PWM timer T₋₋ PWMis cleared when the PZ pulse is outputted to initiate the PZ pulse countinterrupt operation as shown in FIG. 12.

During the PZ drive, it is checked if a counter T₋₋ START, whichmeasures the time since the start, becomes zero (i.e., whether apredetermined period of time has expired). In the case that it is notzero, the counter T₋₋ START is decremented by one and the limit counterT₋₋ LMT is cleared to leave the operation (S2061, S2063, S2069, S2071).This processing is initiated every 2 ms so that the counter T₋₋ START isdecremented every 2 ms. The value of the counter T₋₋ START is set at apredetermined value when the zoom motor is started, but the end pointdetection is not performed within a constant period after that start.

The fact that the counter T₋₋ START becomes zero means that apredetermined time has expired after the motor start, as a result ofwhich the flow advances to the operation of end point detections, fromS2065.

In the case that a duty ratio T₋₋ PWMBRK of the PWM becomes more thanits maximum limit value N₋₋ PWMMAX, the counter T₋₋ LMT for the endpoint detection is incremented by one and the flow advances to S2073. Inthe opposite case, the flow advances directly to S2073 (S2065, S2067).Also, if the motor is engaged in DC drive (i.e., the maximum speeddrive), the value of the maximum limit value N₋₋ PWMMAX, as a duty ratioT₋₋ PWMBRK, is established. Therefore, during the DC drive, the limitcounter T₋₋ LMT is incremented by one (S2065, S2067).

Next, the PWM drive of the zoom motor is controlled as follows.

The PWM duty ratio T₋₋ PWMBRK is usually set at a smaller value than themaximum limit value N₋₋ PWMMAX. Accordingly, the counter T₋₋ LMT is notincremented and the flow exits (S2065, S2073). However, if the PZ pulseis not outputted for a constant period of time, the duty ratio T₋₋PWMBRK is gradually increased by the 2 ms timer routine and becomes avalue similar to the maximum limit value N₋₋ PWMMAX (generally DC drive)after a predetermined period to let the counter T₋₋ LMT be incrementedby one.

Here, in the case of the PWM low speed drive, the value of the PWM dutyratio T₋₋ PWMBRK is small in the beginning. Therefore, upon arrival atthe end point or the para-end point, it takes a long time for thecounter T₋₋ LMT to be incremented.

In the case of the PWM high speed drive, the value of the PWM duty ratioT₋₋ PWMBRK is large. Therefore, upon arrival at the end point or thepara-end point, it takes a shorter time for the counter T₋₋ LMT to beincremented in comparison with that of the PWM low speed drive.

With the above processing, it is possible to change the end pointdetection time depending on the zoom motor drive speed (S2063, S2067).Further, if the counter T₋₋ LMT is below a predetermined value (N₋₋LMT), a predetermined end point detection period will have not yetexpired so that the flow immediately leaves this subroutine (S2073).

If the counter T₋₋ LMT increases beyond the predetermined value N₋₋ LMT,it is regarded as the end pointer the para-end point. In the case of atele-direction drive, a tele end flag F₋₋ TEND is set if a zoom code isa tele end value. However, if the zoom code is not the tele end value,its stop is effected by any abnormality and therefore a para-tele endflag F₋₋ LMTT is set (S2075 to S2081). In the case of a wide-directiondrive, a wide end flag F₋₋ WEND is set if a zoom code is a wide endvalue. However, if the zoom code is not a wide end value, its stop iseffected by any abnormality and therefore a para-wide end flag F₋₋ LMTWis set (S2075, S2083 to S2087).

SET-ST OPERATION

A SET-ST flowchart as shown in FIGS. 72 to 80 is an operation on thepower zoom lens 51 side and is configured to settle a status (speedcontrol bit) such as controls of rotational direction, speed, stop andbrake of the zoom motor. The present operation is a detail of the 2 msinterrupt routine, as shown in FIG. 10. Further, this SET-ST operationincludes, as shown in FIGS. 72 to 80, a MOV operation, an INIT3interrupt operation, a NO-MOVE, a MOV1 operation, BRK1, 2-operation, aSTP1 operation, a MOV-TRG operation and a DRV-TRG8 operation.

Firstly, a power request flag F₋₋ BATREQ is set and the position of thezoom speed change switch 75 is transformed into a predetermined code(which indicates its direction and speed). Thereafter the code is storedin a transformed value memory TRNSSPD (S2101, S2103).

If the lens is driven towards a designated position (F₋₋ MOVTRG=1), theflow advances to the MOV₋₋ TRG operation. If it is a usual move or drivein a designated direction (i.e., when a F₋₋ MOV is set), the flowadvances to the MOV operation (S2105, S2107).

If it does not correspond to any move or drive and a zoom operation ringis located on a neutral position (when the zoom switch 75 is turnedoff), the flow advances to the MOV-TRG operation when in the image sizeconstant zoom mode while the flow advances to the NO-MOV operation whenin the non-image size constant zoom mode (S2109, S2115). If the zoomoperation ring is not located in the neutral position, flow advances tothe NO-MOV operation when a manual power zoom stop bit is set (F₋₋MPZD=1). If not, manual power zooming is being effected and thereforethe flow advances to the MOV operation with a storage of a zoom speeddata, which is transformed from a zoom switch status, in an addressSPDDRC1 (S2109, S2111, S2113).

In the above operation, since upon initiation of a release operation inthe body and the like a flag F₋₋ MPZD is set by a communication commandBODY-STATE1 (22), the manual power zoom operation during the release canbe stopped. Also, upon reception of a transmission of a communicationcommand IPZ-STOP (35) for stopping the power zoom, the respective flagssuch as F₋₋ MOVTRG, F₋₋ MOV and F₋₋ ISZ are cleared and therefore powerzoom operations in addition to the manual power zoom can be stopped.

MOV OPERATION

Next, control of the power zoom motor will be described with referenceto a MOV flowchart, as shown in FIGS. 73 to 75. This control is anoperation in the power lens 51 and concerns manual zooming andcontrolled power zooming in a designated direction (i.e., when the flagF₋₋ MOV is set up).

Firstly, it is checked (i.e., bit 0 of a move direction memory SPDDRC1)if movement is in the tele direction (F₋₋ TELE1=1 (S2201)).

If the direction of movement is in the tele direction and it arrives atthe tele end or para-tele end, the flow advances to the NO-MOV operation(S2201 to S2205). If it is an initial movement (or a start), the flowadvances to an operation S2233 for initialization (S2207). Then, byreference to data concerning the previous zooming motor operation storedin the memory ZM-ST1, which is used for for operating the zoom motor, ifmovement occurred the preceding time, but in a different direction (ofthe zoom motor), or if the power supply from the body is turned off, theflow advances to the brake operation (BRK1 (S2207 to S2211)). If at thepresent time the movement is in the same direction as that of thepreceding operation and the power supply is turned on, the flow advancesto a speed settle operation at S2249 (S2207 to S2211).

If the movement is not in the tele direction, but arrives at the wideend or the para-wide end (F₋₋ WEND=1 or F₋₋ LMTW=1), the flow advancesto the NO-MOV operation (S2201, S2223, S2225). If the lens starts, butdoes not arrive at the wide end or the para-wide end, the flow advancesto a processing S2233 for initialization. If movement occurred thepreceding time, but the present movement is in a different direction orif the power supply from the body is turned off, the flow advances tothe brake operation (BRK1). If the present movement is in the samedirection as that at the preceding movement and if the power supply isturned on, the flow advances to the speed settle operation at S2249(S2225 to S2231).

The initial set up operation upon start-up is executed on condition thatpower from a power source is being supplied. If power is not beingsupplied, the operation proceeds to an ending process (NO-MOV1 (S2233represents the foregoing operation)).

When power is being supplied, the brake counter T₋₋ BRK is incrementedby 1, if the brake flag F₋₋ BRK is set (i.e., when the motor is beingbraked). If the brake counter T₋₋ BRK is less than a predetermined value(N₋₋ BRKREV), the operation proceeds to a brake 2 operation (BRK2) atwhich point a brake is applied (S2235 through S2239).

When the brake flag F₋₋ BRK has been cleared, or if it has been setwhilst brake counter T₋₋ BRK is greater than a predetermined value,braking is completed. In such case, the start up flag F₋₋ START is set,and the limit timer T₋₋ LMT and the PWM timer, T₋₋ PWM, are cleared.Then, a counter is set so that terminal detection does not take placefor a certain period of time after the start-up, and the initial value(i.e., minimum value) of the PWM duty ratio is set (S2235 through S2241represent the foregoing operation). This means, the start flag F₋₋ STARTis set, the terminal detecting counter T₋₋ LMT and the PWM counter T₋₋PWM are cleared, an initial value is entered at the start counter T₋₋START, and a duty ratio T₋₋ PWMBRK of PWM is filled with the minimumvalue. Setting the minimum value at T₋₋ PWMBRK provides the sloweststart-up for PWM.

Upon completion of the setting operation, the LED of the PZ pulser 69 isturned on to prepare for the PZ pulse count. Then, PZ pulse countinterruption (INT3) is enabled, if it was disabled, before proceeding toa speed setting operation (S2249 (S2243 through S2247 represent theforegoing operations)).

In the speed setting operation, a PZ pulse interval (T₋₋ PWMPLS value)is set according to the speed selected. In this case, the time duringwhich electricity is supplied at PWM is controlled so that PZ pulses areoutputted at the selected PZ pulse interval. Four speeds can beselected, although it does need to be limited to four. The speed isselected according to the two bits, bits 2 and 3 (F₋₋ SPDA1,F₋₋ SPDB1),of SPDDRC1. Since the fourth speed is not controlled by PWM control, butrather by DC control, a PZ pulse interval is not set. The maximum valueis set at PWM duty ratio T₋₋ PWMBRK for terminal detection (S2065 inFIG. 71).

Upon completion of the speed selection, the speed and its direction(SPDDRC1) are inputted in the zoom control memory (ZM-ST1), the driveflag F₋₋ DRV is set, and the brake flag F₋₋ BRK is cleared (S2251). Bits3-0 of zoom memory ZM-ST1 (i.e., flags SPD1, SPD0, DRCW, DRCT) are setso that the flags correspond to bits 3-0 of SPDDRC1 (i.e., flags SPDB1,SPDA1, WIDE1, TELE1), respectively. The telephoto end and wide-angle enddummy flags, F₋₋ LMTT and LMTW, are then cleared. The drive directionflags, F₋₋ TMOV, F₋₋ WMOV, F₋₋ TELE1, F₋₋ WIDE1, are set while thetelephoto end and wide-angle end flags, F₋₋ TEND and F₋₋ WEND, arecleared (S2253 through S2257 represent the foregoing operations). F₋₋TMOV, F₋₋ WMOV, F₋₋ TEND and F₋₋ WEND are flags for the PZ-LST data, andare set so that the flags F₋₋ TMOV and F₋₋ WMOV correspond to F₋₋ TELE1,F₋₋ WIDE1 of SPDDRC1, respectively. In the case that either one of F₋₋TMOV and F₋₋ WMOV is set, the other is cleared.

During the zooming operation at a constant image magnification, manualpower zooming is activated by interrupting constant image magnification.Predetermined bits are set at the memory data (PZ₋₋ LST) for the PZconditions of the lens, and the flag is set before processing iscompleted (S2259 and S2267). When zooming is not being performed at aconstant image magnification, if power zooming (manual power zooming) isbeing effected by a zoom switch operation, data including flag F₋₋ MPZfor manual power zooming is set at the zoom condition data (PZ-LST). Ifcontrolled power zooming (i.e., zooming to a specified direction) isbeing effected, data (including flag F₋₋ IPZB) for the controlled powerzooming are entered at the zooming condition data (PZ-LST), before theSET-ST operation is completed (S2261 through S2265 represent theforegoing processes). The content of the PZ₋₋ LST data is transmitted tothe camera body by means of communication using command PZ-LSTATE(10).

INIT3 INTERRUPTION ENABLING OPERATION

FIG. 76 shows an operation that enables interruptions by the PZ pulsecount. In this preferred embodiment, the PZ pulse counting is effectedby software using an interruption of a 2-ms timer. In this process, theenabling bit for the INIT interruption is set to enable counterinterruptions by PZ pulses. This operation shows the details of stepS2247 in FIG. 74 and S2457 in FIG. 82.

NO-MOV and NO-MOV1 OPERATIONS

Flow charts NO-MOV and NO-MOV1 shown in FIG. 77 are operations that stopthe power zooming operation or effect a shift to a braking operation.When power zooming is being effected (i.e., when flag F₋₋ DRV has beenset), the operation proceeds to the BRK1 operation. If power zooming isnot being effected, and if brake is not being effected (i.e., flag F₋₋BRK has been cleared), the operation proceeds to the ending operation(STP1). If brake is being effected, the brake counter is incremented by1, and if the value exceeds a predetermined value (N₋₋ BRK), the endingoperation (STP1) is executed. If the value is less than thepredetermined value, the operation proceeds to Brake 2 (BRK2) tocontinue the braking operation (S2301 through S2307 represent theforegoing processes). Since this NO-MOV1 operation is performed whenpower zooming is not being effected, the process begins from step S2303,skipping step S2301.

BRK1 and BRK2 OPERATIONS

In the brake operation (BRK1) in FIG. 78, the brake timer T₋₋ BRK iscleared and the telephoto direction flag F₋₋ DRCT, wide-angle directionflag F₋₋ DRCW, speed-1 flag F₋₋ SPD0, speed-2 flag F₋₋ SPD1, and thedrive flag F₋₋ DRV are cleared. The brake flag F₋₋ BRK is then set(S2311 and S2313 represent the foregoing processes). Since BRK2 isentered only after the second operation, only step S2313 is executed.After completing the above operations, the SET-ST operation iscompleted.

STP1 OPERATION

The STP1 flow chart shown in FIG. 79 is an operation for stopping thepower zooming operation.

First, the PZ pulse count interruption is disabled, and the LED of thePZ pulser 69 is turned off (S2321 and S2323).

When the zoom switch 75 is at the neutral position, ZM₋₋ ST1 data iscleared (i.e., all the flags are cleared), and a battery request iscancelled (S2327, S2337 and S2347) before proceeding to step S2349. Whenthe zoom switch 75 returns to the neutral position, the dummy terminalflags (F₋₋ LMTT and F₋₋ LMTW) are cleared. Therefore, zooming can alsobe performed in the direction that the dummy terminal was previouslyset.

When the zoom switch 75 is not set at the neutral position, but ratherthe telephoto direction, flags F₋₋ LMTT and F₋₋ LMTW in the ZM₋₋ ST1data are left unchanged, while all the other flags are cleared (S2329,S2331). If the lens is at the telephoto end, or at the para-telephotoend, a battery request is cancelled before proceeding to S2349. If thelens is neither at the telephoto end nor the paratelephoto end, thebattery request is not cancelled, and the operation proceeds to stepS2349 (S2333 and S2335 represent the foregoing processes). When the zoommotor 65 is revolving toward the wide-angle direction, flags F₋₋ LMTTand F₋₋ LMTW in the ZM₋₋ ST1 data are left unchanged, while other flagsare cleared (S2329 and S2341). In the wide-angle end or in thepara-wide-angle end, the battery request is cancelled before proceedingto step S2349. If, however, the lens is neither at the wide end nor thepara-wide-end, the battery request is not cancelled before proceeding tostep S2349 (S2343 and S2345 represent the foregoing processes).

In S2349, whether or not zooming with a constant image magnification isbeing effected is tested. In step S2351, whether or not a calculationfor zooming with a constant image magnification has been completed istested. If zooming with a constant image magnification is in operation,but the calculation has not been completed, flags F₋₋ TEND, F₋₋ WEND,F₋₋ IPZB and F₋₋ ISZOK in the PZ₋₋ LST data are left unchanged, whileother flags F₋₋ TMOV, F₋₋ WMOV, F₋₋ IPZI and F₋₋ MPZ are cleared(S2353). If zooming with a constant image magnification is not beingeffected, or if the calculation has not been completed during zoomingwith a constant image magnification, flags F₋₋ TEND and F₋₋ WEND in thePZ₋₋ LST data are left unchanged, while other flags are cleared (S2355).The content of the data PZ₋₋ LST is transmitted to the camera body 11 bymeans of communication using command PZ-LSTATE (10).

The logical sum of the ZM-ST2 data and a predetermined data is stored inZM-ST2. The start flag F₋₋ START, the zoom flag for constant imagemagnification, F₋₋ ISZ, the specified direction drive flag F₋₋ MOVTARG,the specified position drive flags, F₋₋ MOVPLS and F₋₋ MOVZC, etc. areall cleared, after which the SET-ST operation is completed (S2357). Thismeans, flags F₋₋ PZPOS and F₋₋ PZPDRC in the ZM-ST2 data are leftunchanged, while other flags are cleared.

Flag F₋₋ PZPDRC has the same function as those of flags F₋₋ DRCW and F₋₋DRCT in the data of ZM-ST1. The flag F₋₋ PZPDRC indicates that the lensis driven to the wide end when F₋₋ PZPDRC=1 and that the lens is drivento the tele end when F₋₋ PZPDRC=0.

MOV-TRG OPERATION

The flow chart shown in FIG. 81 is the MOV-TRG operation for driving thezoom lens to a desired position. First, whether or not the targetednumber of PZ pulses is greater than the present PZ pulse is checked(S2401). If it is greater, driving is effected in the telephotodirection, while if it is smaller, driving is effected in the wide-angledirection.

When the driving operation is effected in the telephoto direction, thetargeted number of PZ pulses (PZPTRGT) is subtracted by the presentnumber of pulses (PZPX), and the difference is stored in a memory(PZPDIF) as the number of driving pulses (S2403). If the targeted numberof pulses and the present number of pulses are equal, the operationproceeds to NO-MOV (S2405) because the driving operation is notnecessary. If they are not equal, the direction of the motor drivingoperation is temporarily set for the telephoto direction. If it isneither in the telephoto end or in the para-telephoto end, the operationproceeds to NO-MOV (S2407 through S2411). If it is neither the telephotoend nor para-telephoto end, but during the driving operation, theoperation proceeds to BRK1 if the wide direction flag F₋₋ DRCW is set,or if the battery is turned off (S2413 through S2417). If driving isbeing effected in the same direction, and if the battery is on, theoperation proceeds to DRV-TRG8 (S2413 through S2417). If it is not beingdriven, the operation proceeds to S2441.

When driving is being effected in the wide-angle direction, the targetednumber of pulses (PZPTRGT) is subtracted from the present number ofpulses (PZPX), and the difference is stored in the memory (PZPDIF) asthe number of driving pulses (S2423). The driving direction of the zoommotor is then temporarily set for the wide-angle direction, and if it isin the wide end or in the para-wide end, the operation proceeds toNO-MOV (S2427 through S2431).

If the lens is neither at the wide-angle end nor the para-wide-angleend, but rather in the midst of the driving operation, the operationproceeds to BRK1, if the telephoto direction flag F₋₋ DRCT is on or ifthe battery is turned on (S2433 through S2437). If driving is beingeffected in the same direction, and if the battery is turned on, theoperation proceeds to DRV-TRG8 (S2433 through S2437). If driving is notcurrently being effected, the operation proceeds to S2441.

In this control method, the possibility exists that an excess pulse willoccur as a result of the driving being changed to braking when thetargeted PZ pulses and the present PZ pulses become equal. However,since an excess pulse is of minimal importance, the operation proceedsto NO-MOV1 when the difference pulse PZPDIF is 1, or when it is not 1but power supply is turned off (S2441 through S2443).

When the difference pulse PZPDIF is not 1, and when power supply is on,the brake counter T₋₋ BRK is incremented by 1, if the brake flag F₋₋ BRKis set. If the brake counter T₋₋ BRK is smaller than a predeterminedvalue, the operation proceeds to the braking operation (BRK2 (S2443through S2449 represent the foregoing processes)).

If the brake flag F₋₋ BRK has been cleared, or if the brake counter T₋₋BRK is greater than a predetermined value, the brake operation iscompleted. The start-up flag F₋₋ START is set, and the limit timer andthe PWM timer are cleared. The counter is then set so that terminaldetection is not performed for a certain period of time after start-up,and an initial value (i.e., the minimum value) is set for the PWM dutyratio (S2451). This means, the start flag F₋₋ START is set, the terminaldetecting counter T₋₋ LMT and PWM counter T₋₋ PWM are cleared, aninitial value is entered in the start counter T₋₋ START, and the minimumvalue is entered in the PWM duty ratio T₋₋ PWMBRK.

Upon completion of the setting operation, the LED of the PZ pulser 69 isturned on to prepare for the PZ pulse counting. If PZ pulse interruptionis not enabled, it is enabled before proceeding to DRV-TRG8 (S2453through S2457).

DRV-TRG8 OPERATION

The DRV-TRG8 operation shown in FIGS. 83 and 84 is an operation tocontrol the speed according to the number of the driving PZ pulses untilthe targeted focal distance is reached, and in which speeds are changedin several steps in accordance with the number of pulses to the targetedposition (PZPDIF). In this preferred embodiment, when the number ofdriving pulses to the target is equal to or above that of the thirdpulse, driving is done at the fourth speed (DC driving), which is themaximum speed. When it is less than that of the third pulse, but equalto or above that of the second pulse, driving is done at the thirdspeed. When it is less than that of the second pulse, but equal to orabove that of the first pulse, the second speed is selected. When it isless than that of the first pulse, the first speed is selected. In thisoperation, the fourth speed is greater than the third, which is greaterthan the second, which is greater than the first. The number of thethird pulses is greater than the second, which is greater than thefirst. Also in this preferred embodiment, four speeds can be selected.However, the number of speeds may be more or less than four, or a largenumber of steps for effecting an almost continuously variable speed.

The control proceeds to a speed selection operation in accordance withthe set zoom speed (step S2501). Namely, when a first speed, a secondspeed, a third speed and a fourth speed are selected, the controlproceeds to step S2503, S2511, S2521 and S2541, respectively. Theselection of the speed is effected in accordance with the values of thebits 2 and 3 of SPDDRC2 (i.e., flags F₋₋ SPDA2 and F₋₋ SPDB2) indicatingthe speed at which the zooming is effected to obtain a target value ofthe focal length (i.e., when the flag F₋₋ MOVTRG is set). The speeds areset as follows, in accordance with a combination of a setting andclearing of the flags F₋₋ SPDA2 and F₋₋ SPDB2.

    ______________________________________                                        F.sub.-- SPDA2 F.sub.-- SPDB2                                                 ______________________________________                                        clear          clear        fourth speed                                      clear          set          third speed                                       set            clear        second speed                                      set            set          first speed                                       ______________________________________                                    

The SPDDRC2 is used when the target position is set so that the zoomdirection at the commencement of the drive of the zoom lens and the zoomspeed which is automatically set by the main CPU 35 or the lens CPU 61are stored in the SPDDRC2.

When the first speed is selected, whether or not there are any changesin the speed and its driving direction (the value of ZM-ST1) is tested.If there are changes, the standard value for the first speed N₋₋ PWMMI0is set at the PWM brake timer (PWM duty ratio). If there are not anychanges, nothing is done at this stage. Then the PZ pulse cycle N₋₋PWMP0 of the first speed is set at T-PWMPLS, and the logical sum of R₋₋INT and a predetermined data is stored in ZM-ST1 (i.e., setting of thespeed and its direction (S2503 through S2509 represent the foregoingoperations)). By means of the above operations, the slowest speed isselected. The logical sum of the PZ-LST data and a predetermined data iscomputed. Further logical sum of the above mentioned sum and the R₋₋ INTdata is stored in the PZ-LST data, before the SET-ST operation iscompleted (S2551).

When the second speed is selected, whether or not the number of pulsesto the target position is equal to or above that of the first pulses istested. If it is smaller, the operation proceeds to DRVPWM0 (S2503 forthe first speed). It is equal to or above, the operation proceeds tostep S2513 in which whether there are any changes in speed or itsdirection (i.e., the value of ZM-ST1) is tested to control at the secondspeed. If there are any changes, the standard value of the second speedis set at PWM brake timer (PWM duty ratio). If there are no changes, anoperation is not performed. The cycle N₋₋ PWMP1 of the PZ pulse for thesecond speed is then set at T-PWMPLS. The logical sum of the R₋₋ INTdata and a predetermined data is stored in ZM-ST1 before proceeding toS2551 (S2503 through S2509 represents the foregoing operations whereinthe second speed is selected).

When the third speed is selected, whether or not the number of pulses tothe target position (PZPDIF) is less than that of the first pulses istested. If it is smaller, the operation proceeds to step S2503 (DRVPWM0)for the first speed. If it is equal to or above the number of firstpulses, and less than that of the second pulses, the operation proceedsto DRVPWM1 for the second speed operation (S2521 and S2523). If it isequal to or above the number of second pulses, the control is performedat the third speed. Whether or not there are any changes in speed anddirection (i.e., the value of ZM-ST1) is tested. If there are anychanges, the standard value, N₋₋ PWMMI2 of the third speed, is set atPWM brake timer (PWM duty ratio). If there are no changes, no operationis performed. The cycle N₋₋ PWMP2 of the PZ pulse for the third speed isthen set at T-PWMPLS. The logical sum of the R₋₋ INT data andpredetermined data is stored in ZM-ST1 before proceeding to step S2551.Steps S2523 through S2531 represent the foregoing operations, whereinthe third speed is selected.

When the fourth speed is selected, whether or not the number of pulsesto the target (PZPDIF) is equal to or above that of the first pulses istested. If it is less than the number of first pulses, the operationproceeds to step S2503 (DRVPWM0) for the first speed processing. If itis equal to or above the number of the first pulses, and less than thenumber of the second pulses, the operation proceeds to DRVPW1 for thesecond speed processing. If it is equal to or above the number of thesecond pulses, and less than the number of the third pulses, theoperation proceeds to DRVPWM2. If it is equal to or above the number ofthird pulses, the maximum value N₋₋ PWMMAX is set at the PWM brake timer(PWM duty ratio), and the logical sum of R₋₋ INT data and apredetermined data is set at ZM-ST1, before proceeding to step S2551.Steps S2547 and S2549 represent the foregoing operations. The fourthspeed (DC drive) is selected.

PZP-CNT OPERATION

PZP-CNT flow charts shown in FIGS. 85 through 89 are for operationsregarding the PZ pulse count. These are the details of step S335 in theinterruption routine for a 2 ms timer in FIG. 10.

To calibrate the PZ pulse (i.e., when F₋₋ PZPADJ=0) when the zoom lensgroup 53Z is at the wide-angle end, the present PZ pulse value and thePZ pulse count starting value are reset to zero. Then, if the flag F₋₋PZPOS, which shows whether or not the present position is known, hasbeen set, the operation proceeds to PZP-CNT5. If the present positionflag has been cleared, the operation proceeds to the initializingoperation (PZ-INIT) of the power zoom (S2601 through S2605 and S2615represent the foregoing operations). When calibration is not carriedout, if the present position is known (i.e., when F₋₋ PZPOS=1), theoperation proceeds to the present position OK operation (POS-OK). If thepresent position is unknown (F₋₋ PZPOS=0), the operation proceeds to thepresent position unknown operation (POS-NG (S2603 and S2607 representthe foregoing operations)).

Likewise, to calibrate the PZ pulse when the zoom lens is at thetelephoto end, the present PZ pulse value and the PZ pulse countstarting value are set to the maximum (N₋₋ PZPMAX). If the flag thatshows the present position as being known has been set, the operationproceeds to the PZP-CNT5. If the flag has been cleared, the operationproceeds to the PZ initializing operation (PZ-INT (S2609, S2611, S2613,and S2615 represent the foregoing operations)). When no calibration isneeded, if the present position is known (i.e., when the flag is on),the operation proceeds to the present position OK operation (POS-OK),but if the present position is not known, the operation proceeds to thepresent position unknown (POS-NG) operation (S2611 and S2607). Asexplained above, when the zoom lens group 53Z is at the wide-angle end(F₋₋ WEND=1), or at the telephoto end (F₋₋ TEND=1), the PZ pulse iscalibrated with a predetermined value. F₋₋ PZPADJ is a flag for testing,and when F₋₋ PZPADJ=1, calibration is not performed.

When the lens is neither at the telephoto end nor at the wide-angle end,if the present position is known, the operation proceeds to the presentposition OK operation (POS-OK), but if the present position is unknown,the operation proceeds to the present position unknown operation (POS-NG(S2601, S2611 and S2607 represent the foregoing operations)).

POS-NG AND PZ-INIT OPERATIONS

POS-NG and PZ-INIT, shown in FIGS. 86 and 87, are operations effectivewhen the present position is unknown, or when the telephoto end orwide-angle end has been reached.

The POS-NG and PZ-INIT operations are executed when the present positionof the zoom lens is unknown. Usually, if the present position is notknown, the POS-NG and PZ-INIT operations are also executed when theinitializing command PZ-INITPOS (32) is transmitted from the camera bodywhen the main switch in the camera body is turned on, or when thezooming operation is switched from manual to power.

In the present case, when the PZ-INITPOS command is transmitted, thezoom lens group 53Z is moved toward the telephoto end at the slowestspeed. The present position of the zoom lens group can be detected bystoring the number of absolute PZ pulses in a certain address (PZPX andPZPSTRT) at the position where the first divisional point 72 of the zoomcode plate 71 or the telephoto end is detected. Furthermore, the zoomlens group 53Z is returned to its original position after detecting thepresent position. This can be done by the following procedures. When thePZ₋₋ INITPOS command is transmitted, a counter (PZPAZB) is cleared(making it zero), the first divisional point on the zoom code plate orthe PZ pulse to the telephoto end is counted, and the zoom lens isreturned from that position (i.e., when the present position isdetected) to the position with which the count corresponds. Thisreturning operation of the zoom lens is performed in the PZ-INIToperation (especially in S2637 through S2649).

The operation of the zoom lens at the slowest speed is executed by thePZ-INITPOS command through communication.

In the present case, the lens is driven toward the telephoto end in auniform manner to detect the present position. However, this may betoward the wide-angle end, or either direction may be selected, based onother conditions.

Furthermore, in this present case, when the present position is unknown,it can be detected automatically (i.e., the present position can beknown), even if the PZ₋₋ INITPOS command is not transmitted from thecamera body 51 at the time the lens has reached at a divisional point onthe zoom code plate or a terminal point (i.e., far side and/or nearside) when the manual power zoom is operated.

When the operation enters the POS-NG operation, if the start flag F₋₋START has been set (i.e., at the time the zoom motor is activated), thePZ pulse conversion value (i.e., roughly detected PZ pulse value) on thezoom code plate 71, which is read-in for the operation, is set at thepresent position and the start pulse counter. The operation proceeds tothe zoom driving operation (DRIVSTART1 (S2621 and S2623 represent theforegoing operations)).

The following operation is performed when the start flag F₋₋ START isset OFF. When the zoom code is the same as the previous one, theswitching point has not been reached. The execution then exits thePZP-CNT operation (S2623 and S2625). When the zoom code has been changed(i.e., when at the divisional point on the code plate), the PZ pulseconversion value of the zoom code, which is entered for the presentoperation, is entered as the present PZ pulse value (PZPX) and PZ pulsecount starting value (PZPSTRT), if the driving is toward the telephotoside (F₋₋ PZPDRC=0). If the driving is toward the wide-angle side (F₋₋PZPDRC=1), the PZ pulse conversion value of the zoom code that wasentered previously, is entered as the PZ pulse value (PZPX) and the PZpulse count starting value (PZPSTRT (S2627 through S2631 represent theforegoing operations)).

When the move flag (F₋₋ MOV) has been cleared (i.e., when the PZ₋₋INITPOS command has not been transmitted), or when flag F₋₋ PZPINIT hasbeen set, the flag F₋₋ PZPOS, which indicates recognition of the presentposition, is set when flag F₋₋ PZPINIT has been set before proceeding tothe pulse count (PZP-CNT5) operation (S2633, S2635 and S2649).

When the move flag F₋₋ MOV has been set (i.e., the PZ-INITPOS commandhas been transmitted), and when the present position flag F₋₋ PZPINIThas been turned OFF, the targeted PZ pulse (PZPTRGT) is the present PZpulse value PZPX (i.e., the code plate border value) subtracted by thePZ pulse count value (PZPAZB) from the original position before the PZinitializing to the border position on the code plate (S2633, S2635 andS2637). The F₋₋ PZPINIT is a flag for disabling the initializingoperation of PZ, and is used for testing. When F₋₋ PZPINIT=1, theoperation is disabled.

A borrow in the above subtraction is indicative of an error in thecounting process. In such a case, the targeted number of PZ pulses isset to zero to clear the drive flag F₋₋ MOV. If there is no borrow, themove flag is cleared without any other processing (S2639 and S2641).Then, the move flag for the target value (F₋₋ MOVTRG) is set ON, the PZspeed is set to the first speed (the slowest speed), and the presentposition flag is set ON, after which the operation proceeds to thePZP-CNT5 operation (S2643 through S2649).

When the operation starts at the PZ-INIT operation, S2633 is thestarting set.

POS-OK AND DRVSTRT1 OPERATIONS

The POS-OK operation shown in FIG. 88 is the PZ pulse counting operationin which the present position is known.

When the operation has started already (i.e., the start flag has beencleared), the operation proceeds to the PZ pulse calibrating operation(PZP-ADJ operation). When the operation is about to start, if thedriving operation is effected in the telephoto direction (F₋₋ PZPDRC=0),the sum of the PZ pulse count starting value (PZPSTRT) and the PZ pulsecount value (PZPCNT) is entered into the PZ pulse count starting value(PZPSTRT) and into the present PZ pulse count value (PZPX). If thedriving operation is effected in the wide-angle direction (F₋₋PZPDRC=1), the PZ pulse count starting value (PZPSTRT) is subtracted bythe PZ pulse count value (PZPCNT) and entered into the PZ pulse countstarting value (PZPSTRT) and into the present PZ pulse count value (PZPX(S2651 through S2657 represent the foregoing operations)).

The start flag F₋₋ START is then cleared, and the power zoomingdirection flag F₋₋ PZPDRC is cleared (i.e., the telephoto direction isselected) when the driving operation is effected in the telephotodirection (i.e., the direction toward which the lens is going to movethis time). If the movement is effected in the wide-angle direction(i.e., the current direction toward which the lens is going), the powerzooming direction flag F₋₋ PZPDRC is set (i.e., the wide-angle directionis selected (S2659 through S2665 represent the foregoing operations)).

When the operation begins from DRIVSTART1, step S2659 is the first step.The start flag is cleared, and the driving direction is set in stepsS2659 through S2665.

THE PZP-ADJ AND PZP-CNT5 OPERATIONS

The PZP-ADJ operation, shown in FIG. 89, is for calibrating calculationerrors of the PZ pulse count.

The zoom code is first checked to see if it is the same as the previouscode. If it is the same, the flow exits the PZP-ADJ operation becausecalibration is impossible. If it is different, the calibration operationcontinues, provided that the PZP calibration disabling flag F₋₋ PZPADJhas been cleared, i.e. waits until it exceeds the divisional region(border) of the code plate 71. In this operation, the PZP calibrationdisabling flag F₋₋ PZPADJ is for testing, and is usually cleared.

If the direction of the power zooming operation is toward the telephotodirection, the present pulse conversion value of the zoom code is storedin register X. If the direction is toward the wide-angle direction, theprevious pulse conversion value of the zoom code is stored in registerX, and the value in register X is stored in the accumulator to check ifthe absolute value of the difference between this value and the PZ pulsevalue is within the calibration limit (S2679 through S2683). If itexceeds the calibration limit, the value of register X is stored in thepresent PZ pulse value and in the PZ pulse count starting value toperform calibration. If it is within the calibration limit, nocalibration is performed. The PZ pulse count value (PZPCNT) is cleared,and the number of the PZ pulses at the present focal distance isconverted to the present focal distance (mm) based on table data, and itis then stored in FCLXL and H, after which the execution quits thePZP-CNT operation (S2685 through S2689 represent the foregoingoperations)).

When the operation starts from PZP-CNT5, step S2687 is the first step inwhich the PZ pulse count value is cleared, the number of pulses of thepresent focal distance is converted to the present focal distance (mm),and then stored, after which the execution quits the PZP-CNTE operation(S2685 through S2689).

When there is an instruction to execute a PZ pulse initializingoperation by the above mentioned PZ-INITPOS command from the body (i.e.,when the body main power is turned on), the zooming operation isperformed toward the telephoto side. The present position PZ pulse value(PZPX) and the start position (PZPSTRT) can be selected by detecting theabsolute position from the border position of the divisional region whenit exceeds the divisional region of the code plate 71. Furthermore, theoriginal position can also be returned to after the present position hasbeen detected.

While zooming, every time the border of the code plate 71 is exceeded,the absolute number of pulses at the border part is read-in from thetable and compared with the count value. If the difference is greaterthan a predetermined value, calibration (alteration) is effected.

ISZMEMO OPERATION

The flow chart ISZMEMO shown in FIG. 90 is an operation for storingimage magnification values. In other words, it is an operation whereby,the Present AF pulse value (AFPX) and the present focal length (FCLXLand H) are stored by effecting the zoom speed changing switch 75 or theset switch (SL switch, SW) when in the constant image magnificationzooming mode. This operation is the detail of S359 in the interruptingroutine for a 2 ms timer shown in FIG. 10.

In the present case, the AF pulse value and the focal distance arestored at the time when the zoom ring is returned to the neutralposition, provided an in-focus condition exists, or when the set switchis turned off, even if the zoom lens is not at the neutral position.

In the ISZMEMO operation, the image magnification lens memory flag F₋₋ISM is set, and the constant image magnification mode is selected. Theoperation then proceeds to storing operations of step S2707 and beyond,provided that the in-focus flag F₋₋ AFIN has been set (S2701 throughS2705). The image magnification lens memory flag F₋₋ ISM is transmittedfrom the body by command PZ-BSTATE(20) and is stored in PZ-BDST. Theflag F₋₋ ISM is adapted to determine whether the memorization of theimage magnification should be effected in accordance with the ISZ-MEMORYcommand from the camera body side or the judgement on the lens side.

The image magnification memory flag F₋₋ ISM is usually transmitted afterbeing cleared. Storing of the image magnification memory for the presentAF pulse value and the present focal distance is not performed by thelens alone, but is performed when the command ISZ-MEMORY(36) istransmitted from the body. Furthermore, the transmission of the commandISZ-MEMORY(36) takes place when the zoom speed switch 75 has returned tothe neutral position or when the set switch SL is turned off after thebody checks Bit 2 (SLSW) of the periodical communication POFF-STATE(11)and Bits 0 and 1 (PTSW and PWSW) of LENS-INF1 (13) to determine whetherthe set switch SL (SL switch) and the zoom speed switch 75 are turned onor off.

As explained above, when the flag F₋₋ ISM is set and transmitted, theimage magnification is stored by the lens after determining whether theset switch SL and zoom speed switch 75 are on or off, not by the commandISZ-MEMORY from the body.

When the zoom switch 75 has just been returned to the neutral position,after being in some position other than the neutral position, or whenthe set switch, which was previously ON, has just been turned OFF, thepresent value of the AF pulse is stored at the address ISZ-AFPL and H.The present focal distance is then stored at the address ISZ-FCLL and H,and the image magnification calculation instruction flag F₋₋ ISM is setbefore the ISZMEMO operation is terminated (S2707 through S2719).

In other words, the image magnification is stored in the memory at thetime when the zoom switch 75 has returned from the telephoto orwide-angle side to the neutral position, provided that an in-focuscondition exists and the flag F₋₋ ISM has been set, or when the setswitch is turned off.

MTR-CTL OPERATION

The MTR-CTL flow chart, shown in FIG. 91, is an operation that controlsthe driving operation of the zoom motor 65 corresponding to the zoommotor control flags (i.e., each flag of ZM-ST1) which have been set bythe SET-ST operation. This operation is the detail of S363 in theinterruption routine for the 2-ms timer shown in FIG. 10.

When the drive flag F₋₋ DRV has been cleared and when the brake flag F₋₋BRK has been set, brake is applied to the zoom motor 65. When the brakeflag F₋₋ BRK has been cleared, a 2-ms timer is started after the zoommotor 65 is released. Then, the interruption for the 2 ms timer isenabled, and the PWM interruption is disabled before completing theoperation (S2801, S2809 through S2813, S2817 and S2819 represent theforegoing operations).

When the drive flag F₋₋ DRV has been set, and if it is set fortelephoto, the zoom motor 65 drives the lens toward the telephoto end.If it is set for wide-angle, the zoom motor 65 drives the lens towardthe wide-angle end (S2801 through S2807).

When the motor is actuated at the fourth speed (DC drive), the 2 mstimer is started, the 2 ms timer interruption is enabled, and the PWMinterruption is disabled, before completing the operation (S2815, S2817and S2819).

When the motor is driven at the first through fourth speeds, the PWMhard timer is incremented by 1. When the incremental value overflows,the maximum value (FFH) is assigned to the PWM hard timer. If overflowhas not occurred, the incremental value is maintained (S2815, S2821through S2825).

Next, whether or not the PWM hard timer value (T₋₋ PWM) has exceeded thePWM's PZ pulse cycle (T₋₋ PWMPLS) is determined (i.e., whether the PZpulse is transmitted within the PZ pulse cycle time of PWM). Ifexceeded, the duty ratio (T₋₋ PWMBRK) is increased because the pulse hasnot been transmitted within the cycle time. If not exceeded, the dutyratio (T₋₋ PWMBRK) is set as it is in the hard timer for PWM control,and the hard timer for PWM control is started (S2827 through S2833).Then, the 2 ms timer is started, interruption for the 2 ms timer isenabled, and PWM interruption is enabled before the operation iscompleted (S2835 and S2837).

RELEASE OPERATION

The following discussion will be directed to the release operation (stepS1179 in FIG. 55) in the camera body 11 with reference to FIGS. 92Athrough 92C. The release operation is carried out by the main CPU 35 onthe camera body when the release switch SWR is made ON at step S1176 andwhen it is judged that the releasing can be effected at step S1178.

When the release control operation is commenced, an in-exposure zoomcontrol flag F₋₋ EXZCTL, which indicates the control of the zoom duringthe exposure is cleared at step S4001. The "in-exposure zoom" refers toa zooming operation effected during exposure for at least a part of theexposure time. It is a photographing technique which forms a picturehaving streaks extending radially and in which the image is partiallyextended or contracted. At step S4003, whether or not the power zoomlens 51 is mounted (i.e., whether the power zoom flag F₋₋ PZ is set) ischecked. If no power zoom lens 51 is mounted (F₋₋ PZ=0), that is, if amanually driven zoom lens is mounted, no in-exposure zooming can beautomatically carried out on the camera body side. Consequently, aregular release operation is carried out without effecting thein-exposure zooming.

Namely, the operations at steps S4005, S4007 and S4009 are successivelyeffected to move the mirror upwards, control the diaphragm and move theleading curtain of the shutter, respectively. Thereafter, whether or notthe in-exposure zoom control flag F₋₋ EXZCTL is set is checked at stepS4011. When no power zoom lens 51 is mounted to the camera body at stepS4003, the in-exposure zoom control flag F₋₋ EXZCTL is not set.Consequently, the in-exposure zoom control flag F₋₋ EXZCTL is 0 at stepS4011, since it has been cleared at step S4001.

If F₋₋ EXZCTL=0 at step S4011, whether or not the shutter is in the bulbstate is checked at step S4013. If the shutter is not in the bulb state,the control proceeds to step S4015 to check whether or not thepredetermined exposure time has lapsed. After the lapse of thepredetermined exposure time, the trailing curtain begins moving at stepS4017. If the movement of the trailing curtain is completed at stepS4019, the BODY-STATE1 communication is effected at step S4021. At thesame time, the command to prohibit the manual power zooming and stop thein-exposure zoom is sent to the power zoom lens 51 so that the powersupply from the battery is stopped. Namely, the battery request flag F₋₋BBATREQ on the body side is cleared at step S4023, and the BATONOFFoperation is carried out at step S4025.

Thereafter, the mirror motor 33 is driven to move the mirror downward atstep S4027, and the film winding motor 25 is driven to wind the film atstep S4029. Thereafter, the BODY-STATE1 communication is carried outagain at step S4031. Data representing an absence of the releaseoperation, an absence of the film winding operation, the permission ofthe IPZ operation (i.e., auto zoom operation other than the manual powerzoom), and the permission of the manual power zoom operation is sent tothe power zoom lens 51. Thereafter, the control is returned to the mainroutine shown in FIG. 52.

If the shutter is in the bulb state at step S4013, the control proceedsto step S4017 after the release switch SWR is made OFF at step S4033 tomove the trailing curtain of the shutter and effect the subsequentoperations.

If the power zoom lens 51 is mounted at step S4003, the IPZ-STOP commandis sent to the lens 51 to prohibit the clip zoom operation and theconstant magnification zoom operation before the release operation iscommenced at step S4035. Thereafter, the flags F₋₋ ISZON and F₋₋ IPZONwhich indicate the constant magnification zoom operation and the presetzoom operation are cleared at step S4037. Thereafter, whether or not thein-exposure zoom (EXZ) mode is set is checked at step S4039. If noin-exposure zoom mode is set at step S4039, the BODY-STATE1communication is carried out at step S4041. Accordingly, datarepresenting the release operation, no film winding operation, theprohibition of the IPZ operation and the prohibition of the manual powerzoom operation are sent to the power zoom lens 51. Thereafter, thecontrol proceeds to step S4005 to move the mirror upward. In particular,since the in-exposure zoom control flag F₋₋ EXZCTL is cleared at stepS4011, the regular release operation is carried out.

If the in-exposure zoom mode is set at step S4039, the battery requestflag F₋₋ BBATREQ is set at step S4043 and the BATONOFF operation iscarried out at step S4045 to supply the zoom motor 65 of the power zoomlens 51 with power. Thereafter, the PZ-LSTATE data communication iscarried out at step S4047 so that the data indicating whether the manualpower zoom is made ON or OFF is obtained from the power zoom lens 51.

Whether or not the shutter is set to be in the bulb state is checked atstep S4049. If the shutter is in the bulb state, the BODY-STATE1communication is carried out at step S4051 so that the data on therelease operation, no film winding operation, the prohibition of the IPZoperation and the prohibition of the manual power zooming operation aresent to the power zoom lens 51. Thereafter, the control proceeds to stepS4005 to move the mirror upward.

Namely, when the bulb is set, the exposure time can be optionally set bya photographer even if the in-exposure zoom operation is set.Consequently, since no information on the exposure time can be sent tothe camera body side, it is impossible to define the time at which theautomatic power zooming should be commenced after the start of themovement of the leading curtain, or how long the automatic power zoomingshould continue. Accordingly, the in-exposure zoom is usuallyprohibited. However, in the illustrated embodiment, the manual powerzoom operation is permitted at step S4051 so that the photographer canoptionally perform the zoom operation to effect the in-exposure zoomingwithin a bulb opening time intended by the photographer, as mentionedabove.

Consequently, the photographer can optionally carry out the in-exposurezooming by setting the bulb mode and the in-exposure zoom mode. Namely,the photographer rotates the zoom operation ring 78 about the centeraxis of the lens barrel from the neutral position thereof for a desiredtime in which he or she wants to effect the in-exposure zooming, whilepressing the release switch SWR, i.e., performing the exposureoperation. Consequently, the manual power zooming (in-exposure zooming)can be carried out at the zooming speed corresponding to the angulardisplacement of the zoom operation ring and in the zooming directiondetermined by the direction of the rotation of the zoom operation ring.

If no bulb mode of the shutter is set at step S4049, and a predeterminedshutter speed is set instead, whether or not the in-half-exposurezooming (half MPZ) mode is set is checked at step S4053 prior to theregular in-exposure zooming (i.e., automatic in-exposure zooming whichis automatically carried out on the camera body side). Thein-half-exposure zooming mode refers to a zooming mode in which thein-exposure zooming is not automatically effected but manually effectedby the manual power zooming for a time half the set exposure time. Inother words, the in-half-exposure zooming mode can be considered anassist mode in which power zooming is automatically prohibited for atime half the exposure time in the in-exposure zooming operation by themanual power zooming operation so that the photographer can easilyeffect the in-exposure zooming by the manual power zooming which ismanually effected by the photographer.

If no in-half-exposure zoom mode is selected in the manual power zoom,but the in-exposure zoom mode in which the zooming can be automaticallyeffected on the camera body side is selected at step S4053, whether themanual power zoom is made ON or OFF in accordance with the data readthrough the PZ-LSTATE data communication at step S4047 is checked atstep S4055. If the manual power zoom is made OFF, no in-half-exposurezoom mode is set and accordingly, the control proceeds to step S4057 toset the in-exposure zoom control flag F₋₋ EXZCTL to declare that thein-exposure zooming is being carried out.

Thereafter, the zooming direction (i.e., the wide-angle direction fromthe telephoto extremity towards the wide-angle extremity, or thetelephoto direction from the wide-angle extremity towards the telephotoextremity) of the power zoom lens 51 in the in-exposure zooming is setat step S4059. Thereafter, the power zooming time and the zooming speedin the in-exposure zoom are set at steps S4061 and S4063, respectively.The control processes for setting the zooming direction at step S4059and for setting the zooming speed at step S4063 will be described belowwith reference to the respective sub-routines.

After the operation at step S4063 is completed, the BODY-STATE1communication is carried out at step S4065 to transmit the data on therelease operation, no film winding operation, the prohibition of the IPZoperation and the prohibition of the manual power zoom operation to thepower zoom lens 51. Thereafter, whether the power zooming operation inthe in-exposure zooming is effected in the former half (referred to as aformer half-drive) or latter half (referred to as a latter half-drive)of the exposure time is checked at step S4067.

The former half-drive and the latter half-drive in the in-exposurezooming can be optionally selected by a function selecting/settingswitch (not shown) which is manually actuated by a photographer. If theformer half-drive is selected at step S4067, the MOVE-PZMD command issent to the power zoom lens 51 to move same in a designated direction bya predetermined displacement stored at a designated address of thememory to thereby perform the automatic power zoom operation of thepower zoom lens. Thereafter, the control proceeds to step S4005 to movethe mirror upward. Namely, the power zooming operation is commenced atthe same time as the commencement of the exposure when the formerhalf-drive mode is set in the in-exposure zoom.

If the latter half-drive mode is selected at step S4067, the controlskips step S4069 to go directly to step S4005 to move the mirror upward.In other words, if the latter half-drive mode is selected in thein-exposure zooming operation, no automatic power zooming operation iscommenced by the commencement of the exposure so that the regularexposure is effected.

As can be seen from the above discussion, the exposure operation iscommenced when the in-exposure zoom mode is set whichever mode (formerhalf-drive mode or latter half-drive mode) is selected. After theoperations at steps S4005, S4007 and S4009 are successively completed,the in-exposure zoom control flag F₋₋ EXZCTL is checked at step S4011.Since the flag F₋₋ EXZCTL has been set to 1 at step S4057, whether theformer half-drive or the latter half-drive is selected is checked againat step S4071. If the former half-drive is selected at step S4071, thecontrol proceeds to step S4073 to check whether or not the power zoomdrive time set at step S4061 has expired. After the lapse of the powerzoom drive time, the BODY-STATE1 communication is carried out at stepS4075 so that the data of the release operation, no film windingoperation, the prohibition of the IPZ operation and the prohibition ofthe manual power zooming operation are sent to the power zoom lens 51.Thus, the manual power zoom operation and the automatic power zoomoperation after the lapse of the power zooming time are prohibited, andthen the control proceeds to step S4015 to check whether or not theexposure time has lapsed.

If the latter half-drive mode is selected at step S4071, the controlproceeds to step S4077 to check whether or not the time corresponding toa difference between the set exposure time and the power zoom drivingtime has lapsed. After the lapse of the difference time, whether or notthe in-half-exposure zooming mode (in-exposure manual power zoomingmode) is selected is checked at step S4079. If no in-half-exposurezooming mode is selected at step S4079, the MOVE-PZMD command is sent tothe power zoom lens 51 to move the same in a designated direction by apredetermined displacement stored at a designated address of the memoryto thereby perform the automatic power zoom operation of the power zoomlens (step S4081). Thereafter, the control proceeds to step S4015 inwhich no control proceeds until the set exposure time lapses.

If the switch adapted to select the in-half-exposure zoom mode (halfMPZ) is made ON at step S4053, the in-exposure zoom control flag F₋₋EXZCTL has been set at step S4083, and thereafter, whether or not theformer half-drive mode is selected is checked at step S4085. If theformer half-drive mode is selected at step S4085, whether or not the MPZis made ON, i.e., whether or not the zoom operation ring 78 is rotatedis checked at step S4055. If the MPZ is made OFF, namely, if the zoomoperation ring 78 is not rotated, the control proceeds to step S4057 tosuccessively perform the operations subsequent thereto. Namely, even ifthe in-half-exposure zoom mode in the manual power zooming operation isselected, as long as the zoom operation ring 78 is not rotated, it isassumed that the photographer does not practically intend to commencethe in-half-exposure zooming by the manual power zooming operation sothat the regular in-exposure zooming is carried out.

If the MPZ is made ON at step S4055, namely, if the zoom operation ring78 is rotated, the control proceeds to step S4051 to carry out theBODY-STATE1 communication so that the data of the release operation, nofilm winding operation, the prohibition of the IPZ operation and thepermission of the manual power zooming operation are sent to the powerzoom lens 51. Thus, when the zoom operation ring 78 has been rotated bythe photographer at the commencement of the release operation, theautomatic power zooming operation which is automatically carried out onthe camera body side does not start, and the manual power zooming iscarried out instead at the power zooming speed depending on the angulardisplacement of the zoom operation ring 78 and in the zooming directioncorresponding to the direction of the rotation of the zoom operationring. That is, the former half-drive in the in-half-exposure zoomingoperation by the manual power zooming is effected.

Thereafter, the operations at steps S4005, S4007, S4009, S4011 and S4071are successively effected. After the lapse of the in-exposure zoomingtime in the former half-drive mode, the BODY-STATE1 communication iscarried out at step S4075 so that the data of the release operation, nofilm winding operation, the prohibition of the IPZ operation and theprohibition of the manual power zooming operation are sent to the powerzoom lens 51. Consequently, even if the rotation of the zoom operationring 78 by the photographer continues after the lapse of the in-exposurezooming time, since a further manual power zooming operation isprohibited as mentioned above, the power zooming operation in the formerhalf of the exposure time in the former half-drive mode in thein-half-exposure zooming operation is completed. Thereafter, the regularrelease operation is carried out in the latter half of the posure time,as discussed above with reference to step S4015 and steps subsequentthereto. Thus, the in-half-exposure zooming operation for the formerhalf-drive mode throughout the whole exposure time is completed.

If the in-half-exposure zooming mode is selected at step S4053 and thelatter half-drive mode is selected at step S4085, the control proceedsto step S4057. Namely, the zooming direction, the zooming time and thezooming speed of the in-exposure zooming operation by the manual powerzooming operation to be carried out in the latter half of the exposuretime are successively determined. Thereafter, if the latter half-drivemode is ascertained at step S4071, the control proceeds to step S4077 tocheck whether or not the time corresponding to a difference between theset exposure time and the power zoom driving time has lapsed. After thelapse of the difference time, whether or not the in-half-exposurezooming mode is selected is checked at step S4079. If thein-half-exposure zooming mode is selected at step S4079, the LENS-INF1communication is carried out to send the variable data of the power zoomlens 51 to the camera body 11 at step S4087. Consequently, the ON/OFFstate of the power zoom switch PSZ, which is made ON and OFF by therotation of the zoom operation ring 78, and accordingly the data of thedirection (telephoto direction or wide-angle direction) of the rotationof the zoom operation ring 78 are transmitted to the camera body 11.

Thereafter, at step S4089, whether or not the zoom operation ring 78 isrotated is checked in accordance with the data obtained at step S4087.If the zoom operation ring 78 is rotated, the control proceeds to stepS4091 to effect the BODY-STATE1 communication so that the data of therelease operation, no film winding operation, the prohibition of the IPZoperation and the permission of the manual power zooming operation aresent to the power zoom lens 51. Consequently, the manual power zoomingis carried out at the zooming speed corresponding to the angulardisplacement of the zoom operation ring 78. Namely, the in-half-exposurezooming with the latter half-drive mode by the manual power zoomingoperation is effected.

In the illustrated embodiment, when the in-half-exposure zoom mode inthe manual power zoom is selected, the manual power zooming is carriedout at the zooming speed in accordance with the angular displacement ofthe zoom operation ring 78 rotated by the photographer, regardless ofthe selected drive mode (former half-drive mode or latter half-drivemode). After power zooming in the latter half of the exposure time forthe latter half-drive mode is commenced in response to the permission ofthe manual power zooming at step S4091, the release operation is carriedout, as discussed above with reference to step S4015 and stepssubsequent thereto. Thus, the in-half-exposure zooming operation at thelatter half-drive mode throughout the whole exposure time is completed.

If the zoom operation ring 78 is not rotated at step S4089, it isassumed that the photographer does not practically want to commence thein-half-exposure zooming by the manual power zooming even if thein-half-exposure zoom mode is set. Thus, similarly to the operation atstep S4055, the control proceeds to step S4081 in which the MOVE-PZMDcommand to effect the power zooming to move the zoom lens in apredetermined direction to a predetermined focal length stored in thememory at a designated address is sent to the power zoom lens 51 so thatthe in-half-exposure zooming operation at the latter half-drive modethroughout the whole exposure time is completed.

SUMMARY OF IN-EXPOSURE ZOOM IN RELEASE OPERATION

The control of the in-exposure zooming in the release operation asdiscussed above is summarized in Table 16.

As can be seen from Table 16, when the bulb mode of the shutter is set,the manual power zooming is carried out in an optional period of timedetermined by the photographer regardless of the drive mode (formerhalf-drive or latter half-drive).

In the regular shutter mode in which a predetermined exposure time isset, if the zoom operation ring 78 is rotated when the in-half-exposurezooming with the former half-drive mode is set, the in-exposure zoomcontrol flag F₋₋ EXZCTL is set to permit the manual power zooming onlyin the former half of the exposure time. Namely, no manual power zoomingin the latter half of the exposure time is permitted, and the automaticin-exposure zoom is prohibited throughout the whole exposure time. Ifthe zoom operation ring 78 is not rotated, the automatic power zoomingis carried out only in the former half of the exposure time and nomanual power zooming is permitted in the former half of the exposuretime. Furthermore, in the latter half of the exposure time, no manualpower zooming is permitted and the automatic power zooming is stopped.

If the zoom operation ring 78 is rotated when no in-half-exposurezooming with the former half-drive mode is set, the in-exposure zoomcontrol flag F₋₋ EXZCTL is cleared so that the manual power zooming ispermitted throughout the whole exposure time and the automatic powerzooming is stopped throughout the whole exposure time. If the zoomoperation ring 78 is not rotated, the in-exposure zoom control flag F₋₋EXZCTL is set so that no manual power zooming is permitted throughoutthe whole exposure time and the automatic power zooming is effected inthe former half of the exposure time. The automatic power zooming isstopped in the latter half of the exposure time.

If the in-half-exposure zooming with the latter half-drive mode is setand if the zoom operation ring 78 is rotated, the in-exposure zoomcontrol flag F₋₋ EXZCTL is set so that the manual power zooming ispermitted only in the latter half of the exposure time, and the manualpower zooming is prohibited in the former half of the exposure time.Furthermore, the automatic in-exposure zooming is prohibited throughoutthe whole exposure time. If the zoom operation ring 78 is not rotated,the in-exposure zoom control flag F₋₋ EXZCTL is set so that theautomatic power zooming is effected only in the latter half of theexposure time, and no manual power zooming is permitted in the formerhalf of the exposure time. Furthermore, no manual power zooming ispermitted and the automatic power zooming is prohibited in the formerhalf of the exposure time.

If no in-half-exposure zooming for the latter half-drive mode is set andif the zoom operation ring 78 is rotated, the in-exposure zoom controlflag F₋₋ EXZCTL is cleared so that the manual power zooming is permittedthroughout the whole exposure time, and the automatic power zooming isprohibited throughout the whole exposure time. If the zoom operationring 78 is not rotated, the in-exposure zoom control flag F₋₋ EXZCTL isset so that the manual power zooming is prohibited throughout the wholeexposure time, and the automatic power zooming is permitted in thelatter half of the exposure time and is prohibited in the former half ofthe exposure time.

SETTING OF ZOOMING DIRECTION IN IN-EXPOSURE ZOOMING

The setting process (sub-routine of the release operation) of thezooming direction in the in-exposure zooming at step S4059 will bediscussed below with reference to FIG. 93A.

In the illustrated embodiment, the zooming direction in the in-exposurezooming is determined in accordance with the current focal length set bythe power zoom lens 51, as will become apparent hereinafter.

Namely, in the sub-routine beginning with step S4059, whether or not thezooming direction is predetermined is checked at step S4101. Namely, ifthe zooming direction has been set by the function setting means (notshown) and stored in the E² PROM, the control proceeds to step S4103 toread the zooming direction stored in the E² PROM. Thereafter, thezooming direction read at step S4103 is set in the bit B4 or B5 of theMOVE-PZMD command at step S4105. Thus, the control ends and is returnedto the main routine.

That is to say, if the zooming direction stored in the E² PROM is thetelephoto direction, the bit B4 of the MOVE-PZMD command is set to 1 andthe bit B5 is cleared to be 0, respectively. Conversely, if the zoomingdirection stored in the E² PROM is the wide-angle direction, the bit B4of the MOVEPZMD command is cleared to be 0 and the bit B5 is set to 1,respectively. Consequently, upon the in-exposure zooming, when thesetting operation at step S4059 is carried out, the zooming direction isset at step S4105 so that the power zooming is effected in the setzooming direction.

If no zooming direction has been set at step S4101, the control proceedsto step S4107 to check whether the zoom position (i.e., focal length) ofthe power zoom lens 51 is located at the telephoto extremity orwide-angle extremity in accordance with the bit data of the bit B3 ofthe command PZ-LSTATE obtained at step S4047. If the zoom position islocated at the wide-angle extremity, the control proceeds to step S4109to set the zooming direction to be the telephoto direction in which thezoom lens is moved towards the telephoto extremity. Thus, the controlends and is returned to the main routine. If the zoom position is notlocated at the wide-angle extremity at step S4107, the control proceedsto step S4111 to check whether or not the zoom position of the powerzoom lens 51 is located at the telephoto extremity in accordance withthe bit data B2 of the command PZ-LSTATE. If the zoom position islocated at the telephoto extremity, the control proceeds to step S4113to set the zooming direction to be the wide-angle direction in which thezoom lens is moved towards the wide-angle extremity. Thus, the controlends and is returned to the main routine.

If the zoom position is not located at the telephoto extremity, namely,if the zoom position is located neither at the telephoto extremity norat the wide-angle extremity and is located at an intermediate positionthere between, the bit B3 of the command SET-PZPOINT to instruct thedata to be carried on the command FOCALLEN-X from the camera body to thelens is set 1 at step S4115 to demand the lens to feed the current focallength back to the camera body. Thereafter, at step S4117, the commandFOCALLEN-X is performed to send the current focal lengthfrom the lens tothe camera body.

At step S4119, the bit B1 of the command SET-PZPOINT, to instruct thedata to be carried on the command FOCALLEN-X from the camera body to thelens, is set to 1 to demand the lens to feed the focal length at thewide-angle extremity back to the camera body. Thereafter, at step S4121,the command FOCALLEN-X is performed to send the focal length for thewide-angle extremity from the lens to the camera body. Thereafter, thebit B0 of the command SET-PZPOINT is set to 1 at step S4123 to demandthe lens to feed the focal length for the telephoto extremity back tothe camera body. Thereafter, at step S4125, the command FOCALLEN-X isperformed to send the focal length for the telephoto extremity from thelens to the camera body.

Then, at step S4127, the sum of the focal length at the wide-angleextremity read at step S4121 and the focal length at the telephotoextremity read at step S4125 is multiplied by a constant "A" (e.g., 1/2)which is less than 1, so that whether or not the value thus obtained islarger than the current focal length X read at step S4117 is checked. Ifthe calculated value is larger than the current focal length X at stepS4125, namely, if the current focal length is closer to the telephotoextremity than the intermediate point between the telephoto extremityand the wide-angle extremity, the control proceeds to step S4113 to setthe zooming direction to be the wide-angle direction in which the lensis moved towards the wide-angle extremity. Conversely, if the calculatedvalue is smaller than the current focal length X at step S4125, namely,if the current focal length is closer to the wide-angle extremity thanthe intermediate point between the telephoto extremity and thewide-angle extremity, the control proceeds to step S4109 to set thezooming direction to be the telephoto direction in which the lens ismoved towards the telephoto extremity.

In the illustrated embodiment, the zooming direction is determined sothat the zoom lens is moved towards the wide-angle extremity or thetelephoto extremity, when the current zoom position (focal length) is atthe telephoto extremity or the wide-angle extremity, respectively.Furthermore, if the current zoom position is neither at the telephotoextremity nor the wide-angle extremity, the zoom lens is moved towardsthe wide-angle extremity or the telephoto extremity when the zoomposition is closer to the telephoto extremity than the intermediatepoint between the telephoto extremity and the wide-angle extremity or iscloser to the wide-angle extremity than the intermediate point,respectively. As can be understood from the above discussion, with thepresent invention, the zooming direction for the in-exposure zooming canbe appropriately determined in accordance with the current focal length.

Although the constant "A" referred to at step S4127 is 1/2 in theillustrated embodiment, the present invention is not limited thereto.Namely, the constant "A" can be optionally selected to be any valuesmaller than 1 such as, for example, 1/3.

MODIFIED EMBODIMENT OF SETTING OPERATION OF ZOOMING DIRECTION ININ-EXPOSURE ZOOMING

In the control for setting the zooming direction mentioned above, if thecurrent zoom position (i.e., focal length) is neither at the telephotoextremity nor at the wide-angle extremity, the zooming direction isdetermined in such a way that the zoom lens is moved towards thewide-angle extremity or the telephoto extremity when the zoom positionis relatively closer to the telephoto extremity than the intermediatepoint between the telephoto extremity and the wide-angle extremity or iscloser to the wide-angle extremity than the intermediate point,respectively. The present invention is, however, not limited to such acontrol. For instance, the control can be modified as shown in FIG. 93Bwherein steps corresponding to those in FIG. 93A are designated withlike reference numerals and no detailed explanation thereof will begiven.

In the modified embodiment shown in FIG. 93B, if the current zoomposition is not at the wide-angle extremity at step S4107, the controlproceeds to step S4111' to check whether or not the power zoom lens 51is located at the telephoto extremity or the wide-angle extremity inaccordance with the bit data of the bit B2 of the command PZ-LSTATE,similarly to the aforementioned embodiment. If the zoom position islocated at the telephoto extremity at step S4111', the control proceedsto step S4113 to set the zooming direction to be the wide-angledirection in which the zoom lens is moved towards the wide-angleextremity. When the control ends, it is returned to the main routine.

If the zoom position of the power zoom lens 51 is not at the telephotoextremity at step S4111', namely, if the zoom position is neither at thetelephoto extremity nor the wide-angle extremity in connection with stepS4107 and is in an intermediate position therebetween, the controlproceeds to step S4109 to set the zooming direction to be the telephotodirection in which the lens is moved to towards the telephoto extremity.Thereafter, the control is returned to the main routine.

Namely, in the modified embodiment, only when the current zoom positionof the power zoom lens 51 is located at the telephoto extremity, is thezooming direction set to be the wide-angle direction. In other cases,i.e., if the zoom position is located at the wide-angle extremity or atan intermediate position between the telephoto extremity and thewide-angle extremity, the zooming direction is always set to be thetelephoto direction. This is because in the regular in-exposure zooming,the zooming direction is the telephoto direction in most cases. However,if the zooming direction was always the telephoto direction, no zoomingwould be effected when the zoom position is located at the telephotoextremity so that no in-exposure zooming would be practically carriedout. To prevent this, the zooming direction is set to be the wide-angledirection only when the zoom position is at the telephoto extremity.Thus, the in-exposure zooming which is most frequently used can beeasily effected by a simple control.

SETTING PROCESS OF ZOOMING SPEED IN IN-EXPOSURE ZOOM

The process (sub-routine of the release operation) for setting thezooming speed in the in-exposure zooming operation at step S4063 will bedescribed below with reference to FIG. 93C.

In the operation at step S4063, the zooming speed is predeterminedtaking into account the current focal length, the zooming direction inthe in-exposure zooming and the shutter speed, so that when the exposureis completed, the zoom position does not reach at least the telephotoextremity or the wide-angle extremity whereby the zooming operationwould not be completed.

Namely, if the zooming is completed before the exposure ends, two imagecores will occur in a taken picture, a first image core formed by theexposure in the former half of the exposure time in which no zooming iseffected and a second image core formed by the completion of the zoomingoperation prior to the completion of the exposure in the latter half ofthe exposure time. In particular, if the zooming speed is set inaccordance with the angular displacement of the zoom operation ring 78in the latter half drive of the zooming, the highest zooming speed wouldbe set when the zoom operation ring is rotated through the largestangular displacement by the photographer. In this case, if a longexposure time is set, the zooming would be completed before the exposureends, thus resulting in an occurrence of two image cores in the picture.To avoid this, in the illustrated embodiment, the zooming speed isautomatically set on the camera body side so as not to form the twoimage cores. Consequently, there is no possibility that there are twoimage cores in a taken picture caused by the completion of the zoomingoperation prior to the completion of the exposure.

Furthermore, in the illustrated embodiment, there are four zoomingspeeds including the first lowest speed and the fourth highest speed, sothat an optimum zooming speed can be selected from among them to preventthe occurrence of the two image cores. In an example, the fourth speedis twice the third speed, three times the second speed, and four timesthe first speed, respectively.

In the operation at step S4063, whether or not the zooming speed ispredetermined is checked at step S4201. Namely, if the zooming speed hasbeen set by the function setting means (not shown) and stored in the E²PROM, the control proceeds to step S4203 to read the zooming speedstored in the E² PROM. Thereafter, the zooming speed read at step S4203is set in the bit B6 or B7 of the MOVE-PZMD command at step S4205. Thus,the control ends and is returned to the main routine. Namely, if thezooming speed stored in the E² PROM is the maximum speed, the bit B6 andbit B7 of the MOVE-PZMD command are cleared to 0. Conversely, if thezooming speed stored in the E² PROM is the minimum speed, the bit B6 andbit B7 of the MOVE-PZMD command are set to 1. Consequently, upon thein-exposure zooming, when the setting operation at step S4063 is carriedout, the zooming speed is set at step S4205, so that the power zoomingis effected at the set zooming speed.

If no zooming speed has been set at step S4201, the control proceeds tostep S4207 to check whether the zooming direction set at step S4059 isthe telephoto direction or the wide-angle direction. If the zoomingdirection is the telephoto direction, the control proceeds to step S4209to perform the command PZTIME-XTOT to read the drive time if the powerzooming was to be effected from the current zoom position to thetelephoto extremity at the maximum speed (fourth speed). If the zoomdirection is the wide-angle direction at step S4207, the controlproceeds to step S4211 to perform the command PZTIME-XTOW to read thedrive time if the power zooming was to be effected from the current zoomposition to the wide-angle extremity at the maximum speed (fourthspeed). The commands PZTIME-XTOT and PZTIME-XTOW will be discussed indetail below with reference to their respective sub-routines.

After the drive time corresponding to the telephoto or wide-anglezooming direction is read at step S4209 or S4211, the control proceedsto step S4213 to check whether or not the drive time that has been readis longer than the zooming time for the in-exposure zooming set at stepS4061. If the drive time is longer than the zooming time at step S4213,the control proceeds to step S4215 to select the maximum zooming speed(fourth speed). Namely, even if the zooming speed is set to be themaximum fourth speed, the drive time in which the zoom motor 65 isactually driven is longer than the zooming time in which the zooming inthe in-exposure zooming is carried out within the exposure time, andaccordingly, the zooming will still be continuing when the in-exposurezooming is completed. Consequently, two-image cores will not appear in ataken picture, that is, there is a single image core in a picture.Control is then returned to the main routine.

If the drive time is not longer than the zooming time at step S4213, thecontrol proceeds to step S4217 to check whether or not the doubled drivetime is longer than the zooming time. If the doubled drive time islonger than the zooming time, the control proceeds to step S4219 to setthe zooming speed to be the third speed which is identical to one-halfthe maximum speed. The control is then returned to the main routine.

Namely, if the maximum speed (fourth speed) were to be selected as thezooming speed, the drive time in which the zoom motor 65 is driven wouldexpire before the expiration of the zooming time in which the zoomingfor the in-exposure zooming is effected Within the exposure time. Thus,there would be two image cores in a taken picture, as mentioned above.However, if the zooming speed is set to be the third speed, slower thanthe fourth speed, the drive time becomes longer than the zooming timeand the zooming operation will still be continuing when the in-exposurezooming has been completed. As a result, a taken picture is preventedfrom having two image cores.

If the doubled drive time is still not longer than the zooming time atstep S4217, the control proceeds to step S4221 to check whether or notthe triplicated drive time is longer than the zooming time. If thetriplicated drive time is longer than the zooming time, the controlproceeds to step S4223 to set the zooming speed to be the second speedwhich is one-third the maximum speed. Control is then returned to themain routine.

Namely, if the third speed were to be selected as the zooming speed, thedrive time in which the zoom motor 65 is driven would expire within thezooming time in which the zooming for the in-exposure zooming iseffected within the exposure time. Thus, there would be two image coresin a taken picture, as mentioned above. However, if the zooming speed isset to be the second speed, slower than the third speed, the drive timebecomes longer than the zooming time and the zooming operation is stillcontinuing when the in-exposure zooming is completed. As a result, ataken picture is prevented from having two image cores.

If the triplicated drive time is not longer than the zooming time atstep S4217, the control proceeds to step S4225 to set the zooming speedto be the first speed which is one-fourth the maximum speed. Control isthen returned to the main routine. Namely, if the second speed were tobe selected as the zooming speed, the drive time in which the zoom motor65 is driven would expire within the zooming time in which the zoomingin the in-exposure zooming is effected within the exposure time. Thus,there would be two image cores in a taken picture, as mentioned above.However, if the zooming speed is set to be the first speed (minimumspeed), the drive time becomes longer than the zooming time and thezooming operation will still be continuing when the in-exposure zoomingis completed. As a result, a taken picture is prevented from having twoimage cores.

As can be seen from the above discussion, with the control for settingthe zooming speed of the in-exposure zooming with the present invention,whichever zoom speed is selected, two image cores do not appear in ataken picture, that is, there is a single image core in a picture.

OPERATION OF COMMAND PZTIME-XTOT

The operation of the lens CPU 61 of the power lens 51 when the commandPZTIME-XTOT is output from the body CPU 35 of the camera body 11 at stepS4209 mentioned above will be discussed below with reference to FIG.93D.

When the command PZTIME-XTOT is output from the body CPU 35 of thecamera body 11, the command receipt completion signal is output to thebody CPU 35 on the camera body side from the lens CPU at step S4301.Thereafter, at step S4303, the drive time data is output on theassumption that the lens is moved to the telephoto extremity from thecurrent zoom position (focal length) at the maximum speed (fourthspeed). Thereafter, at step S4305, the data transmission completionsignal is output, and after that, the communication by interruption ispermitted at step S4307. Control is then returned to the main routine.

OPERATION OF COMMAND PZTIME-XTOW

The operation of the lens CPU 61 of the power lens 51 when the commandPZTIME-XTOW is output from the body CPU 35 of the camera body 11 at stepS4211 mentioned above will be discussed below with reference to FIG.93E.

When the command PZTIME-XTOW is output from the body CPU 35 of thecamera body 11, the command receipt completion signal is output to thebody CPU 35 on the camera body side from the lens CPU at step S4311.Thereafter, at step S4313 there is output the drive time data on theassumption that the lens is moved to the wide-angle extremity from thecurrent zoom position (focal length) at the maximum speed (fourthspeed). Thereafter, at step S4315, the data transmission completionsignal is output, and after that, the communication by interruption ispermitted at step S4317, and the control is then returned to the mainroutine.

PZ MODE SWITCHING OPERATION

The power zoom (PZ) mode switching operation of the camera body 11, asshown in FIG. 94, will be explained below. This PZ mode switchingoperation is executed in S1507 of the PZ loop operation shown in FIG.60A, and the PZ mode changing operation is executed when the mode switch77 of the photographing lens 51 is operated. In this preferredembodiment, there are five kinds of zooming modes; the manual zooming ormanual-power zooming, constant image magnification zooming, presetzooming, preset zoom setting and mid-exposure zooming modes. In thisflow chart, each mode has a number; No. 0 is the manual zooming ormanual-power zooming mode, No. 1 is the constant image magnificationzooming mode, No. 2 is the preset zooming mode, No. 3 is the presetzooming setting mode, and NO. 4 is the mid-exposure zooming mode.

First, it is determined if the mounted lens is a power zoom lens and ifthe zoom mode is a manual zoom mode or a power zoom mode. If it isdetermined to be a power zoom lens, it is determined whether it is amanual power zoom (i.e., electric motor driven zoom) or auto-power zoom.If the lens is not a power zoom lens, or power zoom lens but not anautomatic power zoom lens, the power zoom mode flag is cleared. Theoperation maintains these conditions and control is returned (S3001, andS3035).

If the lens is an auto-power zoom lens, the already preserved mode isretrieved. If the lens is in the auto-focus mode, no processing takesplace. However, if it is not in the auto-focus mode, a constant imagemagnification zooming cannot be performed. Therefore, if the retrievedPZ mode is the constant image magnification zooming mode (1), it ischanged to an upper mode. If it is not the PZ mode, no operation takesplace (S3009 through S3013).

Next, when the up and down switches SWUP and SWDN are turned on, achanging operation of the PZ mode is performed (S3015 through S3029)provided that the switch SWAS (i.e., zoom mode switch) of the power zoomlens 51 is turned on. For instance, when the down switch SWDN is turnedon, the zoom mode is changed upward until it becomes No. 4 (S3017, S3031and S3033). When the UP switch SWUP is turned on, the zoom mode ischanged downward until it becomes No. 1. However, when not in theauto-focus mode, constant image magnification is not selected (S3019through S3029).

Upon completion of the UP/DOWN operation, the selected mode number ispreserved, control is then returned (S3039). The state of the switchSWAS is included in the data transmitted by the POFF-STATEcommunication.

THE PZ PULSE COUNT INTERRUPTION OPERATION

The following explains the PZ pulse count interruption operation shownin FIGS. 95 and 96, which is executed in the photographing lens 51. Thisinterruption takes on the rising side of a PZ pulse output, the countingof which is performed by software. The interruption may be performed atthe downfall of a pulse, depending on the setting of the lens CPU.

First, interruption is disabled, and the PZ counter (PZPA2B), whichcounts the PZ pulses in the PZ initializing operation, and the PZ pulsecount value (PZPCNT) are incremented by 1. When the PZ pulse countervalue overflows, the maximum value is entered in the PZ pulse countvalue (S3101 through S3109).

Next, the driving direction of the power zoom lens is checked. If it isin the telephoto direction, the PZ pulse count starting value is addedby the PZ pulse count value and entered into the present PZ pulse value.If it is the wide-angle direction, the PZ pulse count starting value issubtracted by the PZ pulse count value and entered into the present PZpulse value (S3111 through S3115).

Then, when the driving operation is not being performed (F₋₋ DRV=0), theoperation proceeds to the PWM control checking (CHKPWM) in S3117. Whenthe driving operation is being performed, but constant imagemagnification zooming is being effected, or the lens is not being driventowards the targeted position, the operation proceeds to the PWM controlchecking operation (CHKPWM) in S3117 through S3121. When the constantimage magnification zooming is being effected or the lens is beingdriven towards the targeted position, the number of the present PZ pulseand the number of the targeted PZ pulse are not equal, the operationproceeds to the PWM control checking (CHKPWM). If they are equal, theoperation proceeds to the braking operation (BRAK) to immediately stopthe zoom motor (S3117, S3119 and S3123).

THE BRAK AND CHKPWM OPERATIONS

FIG. 96 shows a flow chart regarding the braking operation (BRAKoperation) of the zoom motor and the PWM checking operation. Theseoperations are to reduce the speed of the PZ motor.

In the braking operation, the brake is first applied to the zoom motor(by closing the input terminal of the zoom motor), and the brake data isentered into ZM-ST1. For the brake data, F₋₋ BRK is set, flag F₋₋ LMTTand F₋₋ LMTW remain unchanged, and the others are cleared (S3151 andS3153 represent these operations).

The PWM timer, the limit timer, and the start timer are cleared. Datafor the present focal distance is obtained from the present PZ pulsevalue (PZPX) and stored in FCLXL and H, after which interruption isenabled before control is returned (S3155 through S3159).

The CHKPWM operation is to reduce the duty ratio in the PWM control.When the PWM driving is not in operation, the operation proceeds toS3155 with the fourth speed (DC) unchanged. When the PWM driving is inoperation, if the PWM timer (T-PWM) is less than the PWM pulse cycle(T-PWMPLS), the duty ratio is reduced because the power zooming speed istoo high. The operation then proceeds to S3155. If the PWM timer isgreater than the PWM pulse cycle, the operation proceeds to S3155without any further processes (S3161 through S3165 represent theforegoing operations).

Many functions of this preferred embodiment were explained in theforegoing paragraphs. A part or all of these functions may be built in asingle camera system (i.e., a camera body and a photographing lens).

With the present invention, it is possible to provide various kinds ofcontrols in a power zoom lens and in closer coordination with the camerabody because communication means, to communicate commands and data withthe camera body, is built in both the camera body and the power zoomlens, which is detachably attached to the camera body.

With the present invention, in a single lens reflex camera having apower zoom lens, since the zoom motor 65 is driven for the in-exposurezoom mode to commence the zoom-up or zoom-back when around one-half theexposure time expires (or in the former half of the exposure time), asmentioned above, a clear still object image and a streaked object imagewhich is partly extended or contracted in the radial directions can beobtained.

In addition, as can be seen from the foregoing, with the presentinvention, since the zooming direction of the zoom-up (telephotodirection) or zoom-back (wide-angle direction) is determined by the bodyCPU 35 in accordance with the current focal length, the zoomingoperation can be certainly carried out to ensure the in-exposurezooming. Consequently, it is not necessary for a photographer to set thezooming direction in the in-exposure zooming in the camera, andaccordingly in-exposure zooming, which has hitherto required a highdegree of photographing skill, can be easily effected. Furthermore, nospecial member for setting the zooming direction is necessary, thusresulting in a reduced manufacturing cost. In addition to the foregoing,since there is no possibility that a photographer sets a wrong zoomingdirection by mistake, the photographing reliability can be increased.

In the illustrated embodiment, the zoom operation ring 78 can be rotatedin the clockwise or counterclockwise direction from the neutral positionwhen the shutter is released in the in-exposure zoom mode so that thepower zoom switch is made ON and the in-exposure zooming is not by theregular automatic power zooming, but can be effected by manual powerzooming. Consequently, when the photographer wants to effect thein-exposure zooming under his or her intended conditions (the zoomingdirection, the zooming speed, etc.) different from those preset in thecamera body, the intended conditions can be easily realized by manuallyrotating the zoom operation ring 78, the rotational direction anddisplacement of which determine the zooming direction and the zoomingspeed, respectively.

In the above-mentioned embodiments, when the in-exposure zoom mode isselected, the zooming speed can be set on the camera body side inaccordance with the shutter speed (i.e., exposure time), the set currentfocal length, and the set zooming direction, etc., so that the zoomingoperation is still continuing when the exposure time expires.Consequently, a picture having a single image core and not two imagecores can be obtained.

In the above-mentioned embodiments, when the in-exposure zoom mode isselected, if the bulb (open) mode of the shutter is set, manual powerzoom is permitted. In the prior art, when the bulb (open) mode of theshutter was set, the in-exposure zooming was prohibited since noexposure time can be detected. However, with the present invention,since manual power zooming is permitted, the photographer can effectin-exposure zooming by the manual power zooming, using a part of theexposure time, even if the exposure time is unknown.

In the above-mentioned embodiments, when the in-exposure zoom mode isselected, the manual power zooming can be effected by rotating the zoomoperation ring 78 during the exposure. Consequently, the photographercan effect the in-exposure zooming by the manual power zooming and notby the automatic power zooming, under his or her intended zoomingconditions different from those preset in the camera body for theautomatic power zooming operation.

In the above-mentioned embodiments, when the zoom operation ring 78 isrotated to vary the focal length without pressing the shutter button byhalf step, the focusing is automatically carried out. Consequently, whenthe photographer effects zooming for framing and also observes an objectimage through the view finder, a focused object image can always beviewed through the view finder, thus resulting in improved framing.

In the above-mentioned embodiments, the focusing is automaticallycarried out during the zooming in which the zoom operation ring 78 isrotated without pressing the shutter button by a half step. In thatfocusing, the focusing range (width) can be expanded or extended withrespect to the focusing range for the focusing when the shutter buttonis pressed by a half step to actuate the photometering switch.Consequently, no fine focus adjustments which may be repeatedly effectedare necessary.

In the above-mentioned embodiments, when the zoom set button is pressedat the preset zoom mode, the lens is moved to the stored focal length,and the focusing is effected. Consequently, a camera in which theoperation, particularly at the preset zoom mode (clip mode), issimplified can be provided.

                  TABLE 1                                                         ______________________________________                                                   Instruction                                                        I          Name       Instruction Code                                        ______________________________________                                        0          STANDBY    30                                                      1          AF-INITPOS 31                                                      2          PZ-INITPOS 32                                                      3          RETRACT-PZ 33                                                      4          RET-PZPOS  34                                                      5          IPZ-STOP   35                                                      6          ISZ-MEMORY 36                                                      7          ISZ-START  37                                                      ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                                  Instruction                                                         No        Name         Instruction Code                                       ______________________________________                                        0         LROM 16 byte data                                                                          40                                                     1         LROM first half                                                                            41                                                               8 byte data                                                         2         LROM second half                                                                           42                                                               8 byte data                                                         ______________________________________                                    

                                      TABLE 3                                     __________________________________________________________________________    B                  Data Bit                      dimen-                       L BL COMMAND                                                                             Command Code                                                                          B7 B6 B5  B4  B3  B2  B1  B0  sion                         __________________________________________________________________________    0 PZ-BSTATE                                                                              20      ISM                                                                              AFif                                                                             Mobj                                                                              ovAF                                                                              toFm                                                                              toNm                                                                              endF                                                                              endN                                            1:  lens                                                                             yes                                                                              yes yes yes yes yes yes --                                          0:  body                                                                             no no  no  no  no  no  no                               1 BODY-STATE0                                                                            21      m AF                                                                             swAF                                                                             BATT                                                                              swS Vdd IPZC                                                                              IPZB                                                                              IPZA                                            1:  C  A  yes off on  4   2   1   --                                          0:  S  m  no  on  off                                          2 BODY-STATE1                                                                            22      ISsp                                                                             ISsp                                                                             ISZD                                                                              AF.sup.-- L                                                                       MPZD                                                                              IPZD                                                                              WIND                                                                              REL                                                       pre on  stop                                                                              stop                                                                              yes yes --                                              SP B                                                                             SP A                                                                             AFx off ena.                                                                              ena.                                                                              no  no                               3 SET-AFPOINT.                                                                           23      ISZM                                                                             FM2                                                                              FM1 FM0 X                                            4 SET-PZPOIN.                                                                            24      ISZM                                                                             FM2                                                                              FM1 FM0 X                                            5 STORE-AFP                                                                              25      ISZM                                                                             AM2                                                                              AM1 AM0 2048                                                                              1024                                                                              512 256                                                 128                                                                              64 32   16   8   4  2   1  Pulse                        6 STORE-DEFP&D                                                                           26      SIGN      4096                                                                              2048                                                                              1024                                                                              512 256                                                 128                                                                              64 32   16   8   4  2   1  ×4 μm                                            4096                                                                              2048                                                                              1024                                                                              512 256                                                 128                                                                              64 32   16   8   4  2   1  Pulse                        7 STORE-PZP                                                                              27      AFM                                                                              AM2                                                                              AM1 AM0 PZM FM2 FM1 FM0                                             1:  memo                                                                              4  2    1 memo                                                                                4  2   1  --                                          0:  no            no                                           8 STORE-PZF                                                                              28      ISZM                                                                             FM2                                                                              FM1 FM0     1024                                                                              512 256                                                 128                                                                              64 32   16   8   4  2   1  mm                           9 STORE-IS 29                      2   1 1/2 1/4                                             1/   8 16 32   64  128                                                                               256                                                                              512 1024                                                                              times                        A MOVE-PZMD                                                                              2A      SP B                                                                             SP A                                                                             MD W                                                                              MD T                                                                              MD M                                                                              MvM2                                                                              MvM1                                                                              MvM0                                            1:        wide                                                                              tele                                                                              memo                                                                                4  2   1  --                                          0:        no  no  no                                           B MOVE-PZf 2B      SP B                                                                             SP A           1024                                                                              512 256                                                 128                                                                              64 32   16   8   4  2   1  mm                           __________________________________________________________________________

                                      TABLE 4                                     __________________________________________________________________________    L                 Data Bit                     dimen-                         B LB COMMAND                                                                            Command Code                                                                          B7  B6 B5 B4 B3   B2 B1  B0  sion                           __________________________________________________________________________    0 PZ-LSTATE                                                                             10      MPZ ISok                                                                             IPZI                                                                             IPZB                                                                             Wend Tend                                                                             Wmov                                                                              Tmov                                             1:  on  ng.                                                                              int.                                                                             busy                                                                             end  end                                                                              move                                                                              move                                                                              --                                           0:  off ok ok end                                                                              no   no stop                                                                              stop                               1 POFF-STATE                                                                            11      PH  AFsw                                                                             PZ D                                                                             PZ M                                                                             ASsw SLsw                                                                             LBAT                                                                              Bdet                                             1:  Req.                                                                              AF D  A P                                                                              ON   ON Req.                                                                              on  --                                           0:  no  M  M     OFF  OFF                                                                              no  off                                2 POFFS-WSLEEP                                                                          12      not                          --                                               avai                                                                          labl                                                        3 LENS-INF1                                                                             13      ISmW                                                                              ISmT                                                                             ISdC                                                                             ISdB                                                                             ISdA Lens                                                                             PWsw                                                                              PTsw                                 (Continue)  1:  wide                                                                              tele          A  wide                                                                              tele                                                                              --                                           0:  no  no 1/2                                                                              1/4                                                                              1/8  M  off off                                4 LENS-INF2                                                                             14      exPZ                                                                              exAF                                                                             exAE                                                                             ex B                                                                             rePZ reAF                                                                             verB                                                                              verA                                             1:  yes yes                                                                              yes                                                                              yes                                                                              ok   ok 2   1   --                                           0:  no  no no no ng   ng                                        5 LENS-AFPULSE                                                                          15                   2048 1024                                                                             512 256                                                  128 64 32 16 8    4  2   1   Pulse                          6 FOCALLEN-X                                                                            16                        1024                                                                             512 256                                                  128 64 32 16 8    4  2   1   mm                             7 IMAGE-LSIZE                                                                           17                   2    1  1/2 1/4                                              1/  8   16 32 64 128   256                                                                             512 1024                                                                              times                          __________________________________________________________________________

                                      TABLE 5                                     __________________________________________________________________________    LCO              ADD.sub.-- AE1A (LB4)                                        lens kind  version data                                                                        MTF VNT data (additional data) 1st                           LC1              ADD.sub.-- AE2A (LB4)                                        LENS data        circular flare  data (additional data) 1st                   LC2                                                                           DISTANCE data                                                                 LC3                                                                           K-VALUE data                                                                  LC4              KSF.sub.-- AL   (LBB)                                        abberation correction,                                                                         K-VALUE new communication data LOW                           near distance abberation correction data                                      LC5              KSF.sub.-- AH   (LBB)                                        light color abberation correction data                                                         K-VALUE new communication data HIGH                          LC6                                                                           open abberation data                                                          LC7                                                                           AF minimum actuation condition                                                LC8              CD.sub.-- ZOOMN                                              focal length data                                                                              for zoom code input                                          LC9              CD.sub.-- ZOOMO                                              nominal AVmin AVmax data                                                                       for zoom code input                                          LC10             CD.sub.-- DISN                                               mv' nv' data     for distance code input                                      LC11             CD.sub.-- DISO                                               AVC 1/EXP data   for distance code input                                      LC12             SW.sub.-- ZOOM                                               mv1 AVminsif data                                                                              for zoom SW input                                            LC13             SW.sub.-- KVAL                                               AVmin            for K-VALUE input                                            LC14             SW.sub.-- ZMN                                                UNT.sub.-- 12 UNT.sub.-- 6 data                                                                DM SL PA1                                                                              PA0  SPD2                                                                             SPD1                                                                             SPD0                                     LC15             SW.sub.-- ZMO                                                incorporated flash suited END data                                                             DMO                                                                              SLO                                                                              PA10                                                                             PA00 SPD                                                                              SPD2                                                                             SPD0                                                                    20 10 00                                       __________________________________________________________________________

                                      TABLE 6                                     __________________________________________________________________________    BD.sub.-- ST0 (BL0)             ST.sub.-- PZPOI (BLA)                         MAF SWAF                                                                              BATT                                                                              SWS VDD IPZ2                                                                              IPZ1                                                                              IPZ0                                                                              for SET-PZPINT                                BD.sub.-- ST1 (BL1)             ST.sub.-- AFPOI (BLB)                         IS  IS  ISZD                                                                              AFL MPZD                                                                              IPZD                                                                              WIND                                                                              REL                                               SPB SPA                         for SET-AFPINT                                MOV.sub.-- PZFL (BL2)           POFF.sub.-- ST (LBO, 1)                                                       PH  AFSW                                                                              PZD                                                                              PZM ASSW                                                                              SLSW                                                                              BAT BDET               MOVE-pzf LOW                    REQ                    REQ                    MOV.sub.-- PZFH (BL2)           LNS.sub.-- INF1 (LB2)                         MOVE-pzf HIGH                   ISMW                                                                              ISMT                                                                              ISDC                                                                             ISDB                                                                              ISDA                                                                              LENS                                                                              PWSW                                                                              PTSW               MOV.sub.-- PZMD (BL3)           PZ-LST (LBA)                                                  MPM             MPZ ISOK                                                                              IPZI                                                                             IPZB                                                                              WEND                                                                              TEND                                                                              WMOV                                                                              TMOV               ST.sub.-- PZP (BL4)             SCRT.sub.-- IN (BLF)                          for STORE-PZP                   for secret data input                         ST.sub.-- DEFPL (BL5)           SCRT.sub.-- OUT (LBF)                         AF defocus pulsle of LOW        for secret data output                        ST.sub.-- DEFPH (BL5)           BD.sub.-- VER                                 AF defocus pulse of body HIGH   for BODY VERSION input                        ST.sub.-- DEFL (BL5)            FLG1                                                                          un- GET REC                                                                              BNK RLT RLT OPON                                                                              OP                 AF defocus amount of body LOW   used                                                                              CMD ALC    ON  BNK     BNK                ST.sub.-- DEFH (BL5)            FLG2                                          AF                                                 STN SCK CMD                DRC AF defocus amount of body HIGH                                                                            unused             DBY NG  NG                 ST.sub.-- PZFL (BL6)            COMMAND                                       STORE-pzf LOW                   BODY → LENS COMMAND                    ST.sub.-- PZFH (BL6)            TST.sub.-- ADRH                               STORE-pzf HIGH                  test address data LOW                         ST.sub.-- AFPL (BL7)            TST.sub.-- ADRL                               STORE-AFP LOW                   test address data HIGH                        ST.sub.-- AFPH (BL7)            TST.sub.-- DATA                               STORE-AFP HIGH                  test WRITE data                               PZ.sub.-- BDST (BL9)            TST.sub.-- FLG1                               ISM AFIF                                                                              MOBJ                                                                              OVAF                                                                              FARM                                                                              NEA ENDF                                                                              ENDN                                                                              PZP AFP DM LMT REV PZI PZP AFP                                    RM          CNT CNT    DTC     NIT ADJ ADJ                PZ.sub.-- BDST0                 TST.sub.-- FLG2                               ISMO                                                                              IFO MOB OVA FAR NER END END PUL PUL IO ZMSW                                                                              ZMC DISC                                                                              MTR SET                        JO  FO  MO  RMO FO  NO  LUP LDN                CTL ST                 __________________________________________________________________________

                                      TABLE 7                                     __________________________________________________________________________    R.sub.-- ZOOM, ZM.sub.-- ST1  AFPSTRTL                                        LMTW                                                                              LMTT                                                                              DRV                                                                              BRK                                                                              SPD1                                                                              SPD0                                                                              DRCW                                                                              DRCT                                                                              counter start position AF pulse LOW             SPDDRC1                       AFPSTRTH                                        zoom speed direction                                                                        SPD SPD WID TEL                                                 register 1    B1  A1  E1  E1  HIGH                                            SPDDRC2                       AFPCNTL                                         zoom speed direction                                                                        SPD SPD WID TEL                                                 register 2    B2  A2  E2  E2  AF pulse counter LOW                            TRNSSPD                       AFPCNTH                                         zoom speed SW trans-                                                                        SPDB                                                                              SPDA                                                                              WIDE                                                                              TELE                                                                              HIGH                                            formed value                                                                  PZ.sub.-- LST0                AFPXL                                           MPZO                                                                              IS  IPZ                                                                              IPZ                                                                              WEN TEN WMO TMO                                                     OKO IO BO DO  DO  VO  VO  AF pulse present position LOW                   ZM.sub.-- ST2                 AFPXH                                           un- MOV MOV                                                                              MOV                                                                              ISZ STA PZP PZ                                                  used                                                                              ZC  TRG       RT  DRC POS AF pulse present position HIGH                  ZM.sub.-- ST3                 AFPA2BL                                         unused                REVW                                                                              REVT                                                                              AF pulse generic counter LOW                    T.sub.-- LMT                  AFPA2BH                                         end point detecting timer (counter)                                                                         HIGH                                            T.sub.-- BRK                  AFPCDL                                          zoom motor braking time timer (counter)                                                                     distance code AF pulse transformed value                                      LOW                                             T.sub.-- PWM                  AFPCDH                                          PWM timer (counter)           HIGH                                            T.sub.-- PWMPLS               AFPDIFL                                         PWM PZ pulse period (interval)                                                                              difference between distance code                                              transformed                                                                   value and present positon LOW                   T.sub.-- PWMBRK               AFPDIFH                                         PWM brake timer value (PWM duty ratio)                                                                      HIGH                                            T.sub.-- START                PZPSTRT                                         zoom motor start-up timer (counter)                                                                         PZ pulse at counter start position              T.sub.-- REV                  PZPCNT                                          zoom motor reverse timer      PZ pulse counter                                ZM.sub.-- MODE                PZPX                                            zoom mode                     present position PZ pulse                       ZM.sub.-- DATA                PZPA2B                                          zoom data                     PZ pulse generic counter                        __________________________________________________________________________

                                      TABLE 8                                     __________________________________________________________________________    PZPCD                   ISZ.sub.-- AFPL                                       zoom code PZ pulse transformed value                                                                  ISZ AF pulse LOW                                      PZPDIF                  ISZ.sub.-- AFPH                                       difference between target and present value                                                           HIGH                                                  PZPTRGT                 ISZ.sub.-- FCLL                                       target PZ pulse         ISZ focal length LOW                                  PZPF                    ISZ.sub.-- FCLH                                       target PZ pulse (present value calculate)                                                             HIGH                                                  PZPFPRE                 ISZ.sub.-- IMGL                                       target PZ pulse (predicator calculate)                                                                ISZ image size LOW                                    FCLXL                   ISZ.sub.-- IMGH                                       present focal length LOW                                                                              HIGH                                                  FCLXH                   FCLL                                                  HIGH                    focal length for PZ pulse transform LOW               ISZ.sub.-- ST           FCLH                                                  FPRE                                                                             FPRE                                                                             ISZ                                                                              ISZ                                                                              ISZ                                                                              STIS                                                                             1st                                                                              AF                                                       OK    XOM                                                                              FOM                                                                              M     AFP                                                                              POS                                                                              focal length for PZ pulse transform HIGH              CD.sub.-- DSNEW         UNVCNTR                                               present distance code (remove chattering)                                                             universal counter                                     CD.sub.-- DSOLD         REGC                                                  previous distance code (remove chattering)                                                            generic register C (inhibited to be used                                      other than MAIN)                                      CD.sub.-- DSN           REGD                                                  present distance code   generic register D (inhibited to be used                                      other than MAIN)                                      CD.sub.-- DSO           REGE                                                  previous distance code  generic register E (inhibited to be used                                      other than MAIN)                                      CD.sub.-- ZMNEW         R.sub.-- BE                                           present zoom code (remove chattering)                                                                 generic register R.sub.-- BE (inhibited to be                                 used                                                                          other than MAIN)                                      CD.sub.-- ZMOLD         R.sub.-- CE                                           previous zoom code (remove chattering)                                                                generic register R.sub.-- CE (inhibited to be                                 used                                                                          other than MAIN)                                      CD.sub.-- ZMN           SFT.sub.-- L                                          present zoom code       generic register SFT.sub.-- L (inhibited to be                                used                                                                          other than MAIN)                                      CD.sub.-- ZMO           SFT.sub.-- M                                          present zoom code       generic register SFT.sub.-- M (inhibited to be                                used                                                                          other than MAIN)                                      __________________________________________________________________________

                  TABLE 9                                                         ______________________________________                                        R.sub.-- DEFL        stack area                                               for calculation of FPRE X                                                     R.sub.-- DEFH                                                                 for calculation of FPRE X                                                     R.sub.-- STO                                                                  for serial communication timer-over                                           R.sub.-- DHEN                                                                 for LSB → MSB data transform                                           R.sub.-- ROOP                                                                 for AE AF all data communication                                              R.sub.-- VECTL                                                                for communication interrupt                                                   R.sub.-- VECTH                                                                for communication interrupt                                                   R.sub.-- LROML                                                                LROM first address LOW                                                        R.sub.-- LROMH                                                                LROM first address HIGH                                                       R.sub.-- LROMNL                                                               LCO first address LOW                                                         R.sub.-- LROMNH                                                               LCO first address HIGH                                                        RCONCM                                                                        for storing command during CHBNK                                              R.sub.-- INT                                                                  generic register (for timer interrupt)                                        DUMMY                                                                         for code plate, SW input, WAIT                                                ______________________________________                                    

                  TABLE 10                                                        ______________________________________                                        stack area FCLOL                                                                         FCLOH                                                                         FCL1L                                                                         FCL1H                                                                         FCL2L                                                                         FCL2H                                                                         FCL3L                                                                         FCL3H                                                                         FCL4L                                                                         FCL4H                                                                         FCL5L                                                                         FCL5H                                                                         FCL6L                                                                         FCL6H                                                                         FCL7L RETPOSL                                                                 RET focal length for PZPOS LOW                                                FCL7H RETPOSH                                                                 HIGH                                                               ______________________________________                                    

                  TABLE 11                                                        ______________________________________                                        AFP0L      XOFOL                                                                         ISZ XOFO LOW                                                       AFP0H      XOFOM                                                                         ISZ XOFO MIDDLE                                                    AFP1L      XOFOH                                                                         ISZ XOFO HIGH                                                      AFP1H      ISZ.sub.-- FPXL                                                               PRE operation X LOW                                                AFP2L      ISZ.sub.-- FPXH                                                               PRE operation X HIGH                                               AFP2H      ISZ.sub.-- FL                                                                 ISZ F result LOW                                                   AFP3L      ISZ.sub.-- FH                                                                 ISZ F result HIGH                                                  AFP3H      ISZ.sub.-- FPL                                                                ISZ FPRE result LOW                                                AFP4L      ISZ.sub.-- FPH                                                                ISZ FPRE result HIGH                                               AFP4H                                                                         AFP5L                                                                         AFP5H                                                                         AFP6L                                                                         AFP6H                                                                         AFP7L                                                                         AFP7H                                                                         ______________________________________                                    

                  TABLE 12                                                        ______________________________________                                        F.sub.-- AF                                                                              flag indicating that AF operation is being                                    carried out                                                        F.sub.-- AFIF                                                                            flag indicating that image is focused                              F.sub.-- AFINIT                                                                          flag indicating that initialization of AF is                                  completed                                                          F.sub.-- AFM                                                                             flag designating AF memory                                         F.sub.-- AFPADJ                                                                          flag indicating that correction of AF pulses                                  is prohibited                                                      F.sub.-- AFPOS                                                                           flag indicating that lens CPU correctly                                       recognizes current position of focusing lens                       F.sub.-- AFSW                                                                            flag indicating AF switch data of of lens                          F.sub.-- ASSW                                                                            flag indicating AS switch data of lens                             F.sub.-- BATNG                                                                           flag set when battery voltage is not                                          normally output                                                    F.sub.-- BATON                                                                           flag set when power is supplied to terminal                                   VBATT                                                              F.sub.-- BATREQ                                                                          flag demanding power supply to power zoom lens                     F.sub.-- BATT                                                                            flag indicating that zoom motor is supplied                                   with power from camera body                                        F.sub.-- BBATREQ                                                                         flag demanding activation of power source                                     of power zoom lens by camera body itself                           F.sub.-- BDET                                                                            flag detecting that power source of power                                     zoom lens is activated                                             F.sub.-- BPK                                                                             flag indicating brake of power zoom motor                          F.sub.-- CMDNG                                                                           flag indicating command NG                                         F.sub.-- DRCT                                                                            flag indicating drive of power zoom motor in                                  telephoto direction                                                F.sub.-- DRCW                                                                            flag indicating drive of power zoom motor in                                  wideangle direction                                                F.sub.-- DRV                                                                             flag indicating drive of power zoom motor                          F.sub.-- ENDF                                                                            flag indicating infinite distance                                  F.sub.-- ENDN                                                                            flag indicating closest distance                                   F.sub.-- FARM                                                                            flag indicating movement towards infinite                                     distance                                                           F.sub.-- FPRE                                                                            flag indicating calculation of target value                                   of focal length using defocus pulses at ISZ                                   mode                                                               F.sub.-- FPREOK                                                                          flag indicating that target value of focal                                    length using defocus pulses at ISZ mode has                                   been calculated                                                    F.sub.-- INFOCUS                                                                         flag indicating that image is in focus                             ______________________________________                                    

                  TABLE 13                                                        ______________________________________                                        F.sub.-- IPZB                                                                            flag set by auto zoom other than manual power                                 zoom                                                               F.sub.-- IPZD                                                                            flag determining whether operation similar to                                 IPZSTOP is carried out when BODY-STATE1 is                                    output                                                             F.sub.-- IPZEND                                                                          flag indicating that auto zoom is completed                        F.sub.-- IPZI                                                                            flag indicating that manual power zoom has                                    been effected during ISZ operation                                 F.sub.-- IPZON                                                                           flag indicating that auto zoom is being                                       driven                                                             F.sub.-- IPZSTOP                                                                         flag stopping drive of auto zoom                                   F.sub.-- ISM                                                                             flag determining whether memorization of                                      image magnification based on ISZ-MEMORY                                       command from camera body or judgement on                                      power zoom lens side                                               F.sub.-- ISOK                                                                            flag indicating constant image magnification                                  zoom                                                               F.sub.-- ISSPA                                                                           flag determining control speed of ISZ                              F.sub.-- ISSPB                                                                           flag determining control speed of ISZ                              F.sub.-- ISZ                                                                             flag indicating drive of power zoom motor at                                  ISZ                                                                F.sub.-- ISZD                                                                            control flag at ISZ, which is set and cleared                                 to indicate control of target value of focal                                  length obtained using defocus pulses and                                      control of target value of focal length                                       obtained using current value of AF pulses,                                    respectively                                                       F.sub.-- ISZFOM                                                                          flag indicating calculation of ISZ at focal                                   length transferred from camera body                                F.sub.-- ISZFM                                                                           flag defined at bit 7 of STORE-PZF command                         F.sub.-- ISZMREQ                                                                         flag indicating memorization of image                                         magnification at ISZ                                               F.sub.-- ISZON                                                                           flag indicating ISZ operation                                      F.sub.-- ISZSTOP                                                                         flag indicating stop of drive of ISZ                               F.sub.-- ISZXOM                                                                          flag indicating calculation of ISZ using AF                                   pulses transferred from camera body                                F.sub.-- LBATREQ                                                                         flag demanding battery on power zoom lens                                     side                                                               F.sub.-- LMTT                                                                            flag indicating pseudo-telephoto extremity                         F.sub.-- LMTW                                                                            flag indicating pseudo-wide angle extremity                        ______________________________________                                    

                  TABLE 14                                                        ______________________________________                                        F.sub.-- MDM                                                                            flag reading data from address designated by                                  MYM0-MYM2                                                           F.sub.-- MDT                                                                            flag instructing drive in telephoto                                           direction to power zoom motor                                       F.sub.-- MDW                                                                            flag instructing drive in wide-angle                                          direction to power zoom motor                                       F.sub.-- MOBJ                                                                           flag indicating AF operation in prediction of                                 moving object                                                       F.sub.-- MOV                                                                            flag indicating drive of power zoom motor in                                  a designated direction                                              F.sub.-- MOVTRG                                                                         flag indicating movement of zooming lens to                                   target focal length set at address PZPTRG                           F.sub.-- MPZ                                                                            flag indicating manual power zooming                                F.sub.-- MPZD                                                                           flag indicating prohibition of manual power                                   zooming                                                             F.sub.-- NEARM                                                                          flag indicating movement of power zoom lens                                   towards closest distance direction                                  F.sub.-- NEARMO                                                                         flag indicating previous near-movement                              F.sub.-- NEWCOM                                                                         flag indicating entrance into new                                             communication alter completion of old                                         communication with taking lens                                      F.sub.-- NGTIMER                                                                        flag indicating drive of NG timer                                   F.sub.-- OVAF                                                                           flag indicating overlap integral                                    F.sub.-- PZ                                                                             flag indicating attachment of power zoom lens                                 as taking lens to camera body                                       F.sub.-- PZAFREQ                                                                        flag demanding AF operation during power zooming                    F.sub.-- PZD                                                                            flag indicating selection of manual mode or                                   power mode of switch of power zoom lens                             F.sub.-- PZINIT                                                                         flag indicating initialization of PZ                                F.sub.-- PZM                                                                            flag indicating selection of auto zoom mode                                   or manual power zoom mode of slide switch of                                  power zoom lens                                                     F.sub.-- PZPADJ                                                                         flag prohibiting correction of PZ pulses                            F.sub.-- PZPDRC                                                                         flag which is set and cleared to indicate                                     drive in telephoto direction and wide-angle                                   direction, respectively                                             F.sub.-- PZPINIT                                                                        flag prohibiting return of initialization of PZ                     F.sub.-- PZPOS                                                                          flag indicating that lens CPU correctly                                       recognizes current focal length of zooming                                    lens group                                                          F.sub.-- PZWAIT                                                                         flag prohibiting commencement of power zooming                      F.sub.-- REL                                                                            flag indicating release operation                                   ______________________________________                                    

                  TABLE 15                                                        ______________________________________                                        F.sub.-- SCKNG                                                                           NG flag of synchronization clock signal of                                    serial communication                                               F.sub.-- SIGN                                                                            flag indicating whether or not defocus pulses                                 should be subtracted from current AF pulses                        F.sub.-- SLSW                                                                            flag indicating ON/OFF state of zoom set                                      button of power zoom lens                                          F.sub.-- SPA                                                                             flag designating zooming speed                                     F.sub.-- SPB                                                                             flag designating zooming speed                                     F.sub.-- SPD0                                                                            flag indicating first zooming speed                                F.sub.-- SPD1                                                                            flag indicating second zooming speed                               F.sub.-- SPDA2                                                                           flag indicating zooming speed upon zooming                                    to target focal length                                             F.sub.-- SPDB2                                                                           flag indicating zooming speed upon zooming                                    to target focal length                                             F.sub.-- START                                                                           flag indicating first drive of power zoom                                     motor                                                              F.sub.-- STIS                                                                            flag indicating calculation of ISZ based on                                   image magnification data transferred from                                     camera body                                                        F.sub.-- STNDBY                                                                          flag indicating stop of operation caused by                                   interruption by communication from camera body                     F.sub.-- SWAF                                                                            flag indicating selection of AF/MF switch of                                  camera body                                                        F.sub.-- SWS                                                                             flag indicating operation of photometering                                    switch                                                             F.sub.-- TELE1                                                                           flag indicating drive in telephoto direction                       F.sub.-- TEND                                                                            flag indicating that zooming lens group is                                    located at telephoto extremity                                     F.sub.-- TIMEUP                                                                          flag indicating that set time of timer is up                       F.sub.-- TMOV                                                                            flag indicating drive of power zoom motor in                                  telephoto direction                                                F.sub.-- VDD                                                                             flag indicating that power source of body                                     circuit is made ON                                                 F.sub.-- WEND                                                                            flag indicating that zooming lens group is                                    located at wide-angle extremity                                    F.sub.-- WIDE1                                                                           flag indicating drive in wide-angle direction                      F.sub.-- WMOV                                                                            flag indicating drive of power zoom motor in                                  wideangle direction                                                ______________________________________                                    

                                      TABLE 16                                    __________________________________________________________________________            Drive Time                                                                          Absence of                                                                          Rotation/Stop                                                                              Zoom Control at Former                                                                       Zoom Control at Latter                of    Presence                                                                            of     State of flag                                                                       Half-Drive Mode                                                                              Half-Drive Mode               Bulb or Regular                                                                       Zoom Lens                                                                           of Half MPZ                                                                         Zoom Ring                                                                            F.sub.-- EXZCTL                                                                     MPZ   In-Exposure Zoom                                                                       MPZ   In-Exposure             __________________________________________________________________________                                                          Zoom                    Bulb    --    --    --     0     Permission                                                                          Stop     Permission                                                                          Stop                    Regular(i.e.,                                                                         Former Half                                                                         Half MPZ                                                                            Rotation                                                                             1     Permission                                                                          Stop     Prohibition                                                                         Stop                    a predetermined     Stop   1     Prohibition                                                                         Start    Prohibition                                                                         Stop                    shutter speed NO    Rotation                                                                             0     Permission                                                                          Stop     Permission                                                                          Stop                    is set)             Stop   1     Prohibition                                                                         Start    Prohibition                                                                         Stop                            Latter Half                                                                         Half MPZ                                                                            Rotation                                                                             1     Prohibition                                                                         Stop     Permission                                                                          Stop                                        Stop   1     Prohibition                                                                         Stop     Prohibition                                                                         Start                                 NO    Rotation                                                                             0     Permission                                                                          Stop     Permission                                                                          Stop                                        Stop   1     Prohibition                                                                         Stop     Prohibition                                                                         Start                   __________________________________________________________________________

We claim:
 1. An optical camera, comprising:a zoom lens; a photometeringswitch that is operated to initiate a focusing operation; means forchanging a focal length of said zoom lens; automatic focusing means forautomatically effecting said focusing operation of said zoom lens withrespect to an object to be photographed by said camera in response tosaid changing means changing said focal length of said zoom lens; andcontrol means for activating said focusing operation by said automaticfocusing means when said focal length is changed by said focal lengthchanging means, even if said photometering switch is not operated toinitiate said focusing operation.
 2. A camera as claimed in claim 1,further comprising a manually operable shutter button, wherein saidautomatic focusing means is actuated in response to an actuation of saidshutter button.
 3. A camera as claimed in claim 1, wherein said controlmeans actuates said focusing operation by said automatic focusing meansupon a commencement of said changing of said focal length of said zoomlens.
 4. A camera as claimed in claim 1, wherein said control meansactuates said automatic focusing means during said changing of saidfocal length of said zoom lens.
 5. A camera as claimed in claim 1,wherein said control means actuates said automatic focusing means upon astopping of said changing of said focal length of said zoom lens.
 6. Acamera as claimed in claim 1, wherein said zoom lens comprises a motordriven zoom lens.
 7. A camera as claimed in claim 6, wherein a motor fordriving said zoom lens is located in a body portion of said zoom lens.8. A camera as claimed in claim 7, wherein said focal length changingmeans is mounted to an outer peripheral surface of said zoom lens so asto rotate about an optical axis to vary said focal length of said zoomlens.
 9. A camera as claimed in claim 8, wherein said focal lengthchanging means comprises a zoom ring that is elastically biased to aneutral position so that when said zoom ring is rotated from saidneutral position in one of a clockwise or counterclockwise direction,said focal length of said zoom lens is changed.
 10. A camera as claimedin claims 9, wherein said zoom lens is detachably mounted to a body ofsaid camera.
 11. A camera as claimed in claim 1, furthercomprising:means for obtaining distance data of said object to bephotographed from said camera; means for detecting a neutral position ofsaid focal length changing means, wherein said control means actuatessaid automatic focusing means when said neutral position is detected;and means for calculating an image magnification of an object image inaccordance with said object distance data obtained by said obtainingmeans and a current focal length when said focusing operation iscompleted.
 12. A camera as claimed in claim 11, further comprising:meansfor storing calculation results of said image magnification calculationmeans.
 13. A camera as claimed in claim 12, further comprising amanually operable shutter button, wherein said automatic focusing meansis actuated in response to an actuation of said shutter button.
 14. Acamera as claimed in claim 13, wherein said control means actuates saidautomatic focusing means when said shutter button is actuated within afocusing range which is different from a focusing range of saidautomatic focusing means when said focal length is being changed.
 15. Acamera as claimed in claim 14, wherein said focusing range is smallerwhen said shutter button is actuated than a focusing range when saidfocal length is being changed.
 16. A camera as claimed in claim 15,wherein said zoom lens comprises a motor driven zoom lens.
 17. A cameraas claimed in claim 16, wherein a motor for driving said zoom lens islocated in a body portion of said zoom lens.
 18. A camera as claimed inclaim 17, wherein said focal length changing means is mounted to anouter peripheral surface of said zoom lens so as to rotate about anoptical axis to vary said focal length of said zoom lens.
 19. A cameraas claimed in claim 18, wherein said focal length changing meanscomprises a zoom ring elastically biased to a neutral position so thatwhen said zoom ring is rotated from said neutral position in one of aclockwise or counterclockwise direction, said focal length of said zoomlens is changed.
 20. An optical camera, comprising:a motor driven zoomlens; a photometering switch that is operated to initiate a focusingoperation; means for changing a focal length of said motor driven zoomlens; automatic focusing means for effecting said focusing operation ofsaid zoom lens with respect to an object to be photographed by saidcamera in response to a change in said focal length of said motor drivenzoom lens; an actuating member associated with said motor driven zoomlens; control means for activating said automatic focusing means whensaid actuating member has been actuated, even if said photometeringswitch is not operated to initiate said focusing operation; means forobtaining distance data of said object to be photographed by saidcamera; and image magnification calculation means for calculating animage magnification of said object in accordance with said objectdistance data and a current focal length when said focusing operation iscompleted by said automatic focusing means.
 21. A camera as claimed inclaim 20, further comprising means for storing calculation results ofsaid image magnification calculation means.
 22. A camera as claimed inclaim 20, wherein said actuating member is provided on said zoom lens.23. An optical camera, comprising:a motor driven zoom lens; aphotometering switch that is operated to initiate a focusing operation;means for changing a focal length of said motor driven zoom lens;automatic focusing means for effecting focusing operation of said lenswith respect to an object to be photographed by said camera in responseto a change in said focal length of said motor driven zoom lens; anactuating member associated with said motor driven zoom lens; andcontrol means for activating said automatic focusing means when saidactuating member has been actuated, even if said photometering switch isnot operated to initiate said focusing operation, wherein said actuationof said actuating member moves said motor driven zoom lens to adetermined position.
 24. A camera as claimed in claim 23, wherein saidfocusing operation is commenced when said determined position isattained.
 25. A camera as claimed in claim 23, further comprising meansfor storing a focal length corresponding to said determined position.26. A camera as claimed in claim 25, wherein said storing meanselectronically stores said determined position.
 27. A camera as claimedin claim 25, wherein said storing mechanically means stores saiddetermined position.
 28. A camera as claimed in claim 23, wherein saiddetermined position corresponds to a position on a display of saidcamera.
 29. A camera as claimed in claim 24, wherein said actuatingmember is provided on said zoom lens.
 30. A camera as claimed in claim29, wherein said control means controls said storing means to store acurrent focal length when said actuating member is activated in a setmode, said control means controlling said zoom lens to move to saidstored focal length, said controlling means commencing said focusingoperation when said actuating member is activated in an operation mode.31. A camera as claimed in claim 30, wherein said control means ismounted in said zoom lens.
 32. A camera as claimed in claim 31, whereinsaid zoom lens is detachably mounted to a body of said camera.
 33. Acamera, comprising:a camera body; a zoom lens; a photometering switchthat is operated to initiate a focusing operation; focal length settingmeans for changing a focal length of said zoom lens; an automaticfocusing device for automatically focusing said zoom lens on an objectto be photographed in response to a change in said focal length of saidzoom lens by said focal length setting means, even if said photometeringswitch is not operated to initiate said focusing operation; and acontrol device for controlling functions of said camera, wherein saidfocal length setting means is coupled with said automatic focusingdevice via said control device such that said automatic focusing iscarried out in accordance with an actuation of said focal length settingmeans.
 34. A camera according to claim 33, wherein said automaticfocusing is started simultaneously with said actuation of said focallength setting means.
 35. A camera according to claim 33, wherein saidfocal length setting means has a zoom ring rotatably arranged on anouter circumference of said zoom lens and coaxial to an optical axis ofsaid zoom lens.
 36. A camera according to claim 34, wherein saidautomatic focusing device has means for controlling a focusing range ofsaid zoom lens which establishes a first focusing range when saidautomatic focusing device is actuated by actuating a shutter releasebutton of said camera, and which establishes a second focusing rangewhen said automatic focusing is carried out during an actuation of saidfocal length setting means.
 37. A camera according to claim 36, whereinsaid first focusing range is smaller than said second focusing range.38. A camera according to claim 33, wherein said focal length settingmeans has a zoom drive for an automatic modification of said focallength of said zoom lens and a drive control member.
 39. A cameraaccording to claim 38, wherein in said zoom drive is arranged in saidzoom lens.
 40. A camera according to claim 38, wherein in said drivecontrol member comprises a zoom ring.
 41. A camera according to claim38, wherein said camera further comprises memory means for storing afocal length set in said zoom lens, and that said drive control membercomprises a memory control member, an actuation of which controls saidzoom drive, in order to set said zoom lens at a focal length stored insaid memory means, said actuation of which automatically actuates saidautomatic focusing device at the same time.
 42. A camera according toclaim 41, wherein in said memory control member includes a zoom setbutton arranged on said zoom lens.
 43. A camera according to claim 42,wherein a mode selection device enables said camera to switch between afirst operation mode, in which a focal length set at said zoom lens isstored in said memory means by actuating said memory control member, anda second operation mode, in which said memory control member controlssaid zoom drive and triggers said automatic focusing.
 44. A cameraaccording to claim 43, wherein said automatic focusing device has meansfor controlling a focusing range of said camera which establishes afirst focusing range when said automatic focusing device is actuated bya shutter release button of said camera, and which establishes a secondfocusing range when said automatic focusing is carried out during amodification of said focal length of said zoom lens.
 45. A cameraaccording to claim 44, wherein in said first focusing range is smallerthan said second focusing range.
 46. A camera, comprising:control meansfor controlling functions of said camera; a camera body; a photometeringswitch that is operated to initiate a focusing operation; a zoom lenshaving zoom drive means for changing a focal length of said zoom lens; afocal length adjusting member for actuating said zoom drive means; anautomatic focusing device for automatically focusing said zoom lens onan object to be photographed in response to a change in said focallength of said zoom lens; distance measuring means for detecting adistance of said object to be photographed; mode selection means forselecting a camera operation mode with a constant image scale;calculating means for calculating said image scale from a set focallength and said detected object distance; a memory for storing saidcalculated image scale; and a control member, arranged on said lens, foractuating said calculating means, wherein said control member is coupledto said automatic focusing device via said control means such that anautomatic focusing is started in response to an actuation of saidcontrol member, even if said photometering switch is not operated toinitiate said focusing operation, said calculating means calculatingsaid image scale on the basis of said object distance detected upon acompletion of said automatic focusing, said image scale being stored insaid memory.
 47. A camera according to claim 46, wherein in said controlmember comprises a zoom setting button arranged on said lens.
 48. Acamera according to claim 46 wherein said control means comprises saidfocal length adjusting member, a resting position detector beingprovided for detecting a resting position of said focal lengthadjustment member corresponding to a stopping of said zoom drive means,said calculating means being actuated by said control means inaccordance with said focal length adjusting member returning to saidresting position.
 49. A focusing system for a camera having a zoom lens,comprising:a photometering switch that is actuated to initiate afocusing operation of the zoom lens; an automatic focusing device thateffects said focusing operation of the zoom lens; and a controller thatperforms said focusing operation by said automatic focusing device whena focal length of the zoom lens is changed, even if said photometeringswitch is not operated to initiate said focusing operation.
 50. Thefocusing system of claim 49, further comprising:a constant imagemagnification controller that maintains a constant magnification of anobject to be photographed by varying said focal length of the zoom lens,said controller performing said focusing operation in response to achange in said focal length of the zoom lens by said constant imagemagnification controller, even if said photometering switch is notoperated to initiate said focusing operation.